Accessing Plugin list

Hey guys, I get 503 (The remote server returned an error: (503) Service Temporarily Unavailable.) Error if I like to use my plugins list. The strange thing is that I can open this list from another computer. In addition in the log report I find the path to the project source code, which lies elsewhere now. I DO NOT UNDERSTAND WHAT IS THE PROBLEM HERE. Enclosed log report:
please contact me (info[at]licht-platz.de)
----- REPORT below------------
System.Net.WebException: The remote server returned an error: (503) Service Temporarily Unavailable.
   at System.Net.HttpWebRequest.GetResponse()
   at Nop.Core.Plugins.OfficialFeedManager.GetDocument(String feedQuery, Object[] args) in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Libraries\Nop.Core\Plugins\OfficialFeedManager.cs:line 25
   at Nop.Core.Plugins.OfficialFeedManager.GetVersions() in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Libraries\Nop.Core\Plugins\OfficialFeedManager.cs:line 70
   at Nop.Web.Areas.Admin.Factories.PluginModelFactory.PrepareOfficialFeedPluginSearchModel(OfficialFeedPluginSearchModel searchModel) in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Presentation\Nop.Web\Areas\Admin\Factories\PluginModelFactory.cs:line 249
   at Nop.Web.Areas.Admin.Factories.PluginModelFactory.PreparePluginsConfigurationModel(PluginsConfigurationModel pluginsConfigurationModel) in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Presentation\Nop.Web\Areas\Admin\Factories\PluginModelFactory.cs:line 357
   at Nop.Web.Areas.Admin.Controllers.PluginController.List() in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Presentation\Nop.Web\Areas\Admin\Controllers\PluginController.cs:line 111
   at lambda_method(Closure , Object , Object[] )
   at Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeActionMethodAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeNextActionFilterAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
   at Microsoft.AspNetCore.Builder.RouterMiddleware.Invoke(HttpContext httpContext)
   at StackExchange.Profiling.MiniProfilerMiddleware.Invoke(HttpContext context) in C:\projects\dotnet\src\MiniProfiler.AspNetCore\MiniProfilerMiddleware.cs:line 94
   at Nop.Plugin.Api.ApiStartup.<>c.<<Configure>b__2_0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at IdentityServer4.Hosting.IdentityServerMiddleware.Invoke(HttpContext context, IEndpointRouter router, IUserSession session, IEventService events)
   at Microsoft.AspNetCore.Cors.Infrastructure.CorsMiddleware.Invoke(HttpContext context)
   at IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext context)
   at Nop.Plugin.Api.IdentityServer.Middlewares.IdentityServerScopeParameterMiddleware.Invoke(HttpContext context)
   at Nop.Services.Authentication.AuthenticationMiddleware.Invoke(HttpContext context) in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Libraries\Nop.Services\Authentication\AuthenticationMiddleware.cs:line 79
   at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext context)
   at Nop.Core.Http.InstallUrlMiddleware.Invoke(HttpContext context, IWebHelper webHelper) in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Libraries\Nop.Core\Http\InstallUrlMiddleware.cs:line 51
   at Nop.Core.Http.KeepAliveMiddleware.Invoke(HttpContext context, IWebHelper webHelper) in C:\Users\rolan\Desktop\____BussinesFolder\_SORT_ (2)\l4u_410_Source\Libraries\Nop.Core\Http\KeepAliveMiddleware.cs:line 50
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.StatusCodePagesMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.StatusCodePagesMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware.Invoke(HttpContext context)

If you are using the NopCommerce version 4.1 then you can't access the plugin page because of NopCommerce implementing Cloudflare DDoS protection. For more information and fix please check this thread.