IIS frequently shutdown

IIS server configured for our website seems to be shutting down on alternate days. We have set the keep alive scheduled task to work in 300 sec but still the website gets shut down on alternate days. Can anyone help us on this?

Do you see "Application started " in the System log?
What version of nopcommerce?
Are you using a hosting service or is it your server?

Do you see "Application started " in the System log?
=> Application started is present in the start of the log and at the end,
info: Microsoft.Hosting.Lifetime[0]
      Application is shutting down...
We have to manually restart the IIS server whenever this situation occurs.

What version of nopcommerce?  
=> nopCommerce_4.40.3

Are you using a hosting service or is it your server?
=> Azure Server

What 'log' are you seeing that message in?
NopCommerce "System Log"?
Azure's Application Insights?

Saw this is nopcommerce system log. And after this shutting down message in log, website shows "An error occured while starting the application". When IIS restarted, the website works fine.

Post the entire message text here.  (including stack trace if present)

Posting last 200 lines in the log

info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 58
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "RunTask", controller = "ScheduleTask", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] RunTask(System.String) on controller Nop.Web.Controllers.ScheduleTaskController (Nop.Web).
info: System.Net.Http.HttpClient.StoreHttpClient.LogicalHandler[100]
      Start processing HTTP request GET http://abcdefg.com/keepalive/index
info: System.Net.Http.HttpClient.StoreHttpClient.ClientHandler[100]
      Sending HTTP request GET http://abcdefg.com/keepalive/index
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 GET http://abcdefg.com/keepalive/index - -
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 GET http://abcdefg.com/keepalive/index - - - 200 0 - 3.8701ms
info: System.Net.Http.HttpClient.StoreHttpClient.ClientHandler[101]
      Received HTTP response headers after 51.0362ms - 200
info: System.Net.Http.HttpClient.StoreHttpClient.LogicalHandler[101]
      End processing HTTP request after 51.1057ms - 200
info: Microsoft.AspNetCore.Mvc.StatusCodeResult[1]
      Executing HttpStatusCodeResult, setting HTTP status code 204
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web) in 59.2449ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 58 - 204 - - 75.9568ms
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 97.4308ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 97.5187ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "RunTask", controller = "ScheduleTask", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] RunTask(System.String) on controller Nop.Web.Controllers.ScheduleTaskController (Nop.Web).
info: Microsoft.AspNetCore.Mvc.StatusCodeResult[1]
      Executing HttpStatusCodeResult, setting HTTP status code 204
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web) in 889.4401ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69 - 204 - - 898.7405ms
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 934.7067ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 934.9153ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 63
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "RunTask", controller = "ScheduleTask", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] RunTask(System.String) on controller Nop.Web.Controllers.ScheduleTaskController (Nop.Web).
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "RunTask", controller = "ScheduleTask", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] RunTask(System.String) on controller Nop.Web.Controllers.ScheduleTaskController (Nop.Web).
info: Microsoft.AspNetCore.Mvc.StatusCodeResult[1]
      Executing HttpStatusCodeResult, setting HTTP status code 204
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web) in 960.8042ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69 - 204 - - 966.0979ms
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 1512.5602ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 1512.6666ms - 204
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 99009.2832ms - 524
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 99009.4277ms - 524
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "RunTask", controller = "ScheduleTask", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] RunTask(System.String) on controller Nop.Web.Controllers.ScheduleTaskController (Nop.Web).
info: Microsoft.AspNetCore.Mvc.StatusCodeResult[1]
      Executing HttpStatusCodeResult, setting HTTP status code 204
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web) in 983.6844ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69 - 204 - - 991.2843ms
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 2638.4943ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 2638.7641ms - 204
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 GET http://abcdefg.com/iphone-13-pro-max - -
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.CatalogController.Category (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "Category", controller = "Catalog", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] Category(Int32, Nop.Web.Models.Catalog.CatalogProductsCommand) on controller Nop.Web.Controllers.CatalogController (Nop.Web).
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.CatalogController.Category (Nop.Web) in 9.6995ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.CatalogController.Category (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 GET http://abcdefg.com/iphone-13-pro-max - - - 500 - application/json 25.4566ms
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "RunTask", controller = "ScheduleTask", area = ""}. Executing controller action with signature System.Threading.Tasks.Task`1[Microsoft.AspNetCore.Mvc.IActionResult] RunTask(System.String) on controller Nop.Web.Controllers.ScheduleTaskController (Nop.Web).
info: Microsoft.AspNetCore.Mvc.StatusCodeResult[1]
      Executing HttpStatusCodeResult, setting HTTP status code 204
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web) in 994.6052ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 69 - 204 - - 1007.9499ms
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 2012.5547ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 2012.6829ms - 204
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 1799.2311ms - 500
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 1799.5421ms - 500
info: System.Net.Http.HttpClient.default.LogicalHandler[100]
      Start processing HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[100]
      Sending HTTP request POST https://abcdefg.com/scheduletask/runtask
info: System.Net.Http.HttpClient.default.ClientHandler[101]
      Received HTTP response headers after 564.6745ms - 500
info: System.Net.Http.HttpClient.default.LogicalHandler[101]
      End processing HTTP request after 564.8864ms - 500
info: Microsoft.AspNetCore.Mvc.StatusCodeResult[1]
      Executing HttpStatusCodeResult, setting HTTP status code 204
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web) in 239984.9276ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'Nop.Web.Controllers.ScheduleTaskController.RunTask (Nop.Web)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://abcdefg.com/scheduletask/runtask application/x-www-form-urlencoded 63 - 204 - - 239989.9343ms
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://127.0.0.1:26819/iisintegration - 0
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 POST http://127.0.0.1:26819/iisintegration - 0 - 202 0 - 0.6217ms
info: Microsoft.Hosting.Lifetime[0]
      Application is shutting down...

I am similar to the two of them, a problem
in 4.6.2

Can you post your entire error message from the logs?