Application is shutting down - Nop 4.00

Goodmorning everyone. I have updated a site of one of my clients from version 3.40 to version 4.00. I installed a new theme and everything went well for a couple of days. Suddenly the application started to go wrong. Looking at the log files I saw that the error is denied access on a dll, first that of a plugin and then after removing that plugin I saw that the same happens for another plugin. The error is as follows:

Application startup exception: System.Exception: Plugin 'ECB exchange rate provider'. Access to the path 'C:\HostingSpaces\admin1\spyitalia.it\wwwroot\Plugins\bin\Nop.Plugin.ExchangeRate.EcbExchange.dll' is denied.
Access to the path 'C:\HostingSpaces\admin1\spyitalia.it\wwwroot\Plugins\bin\Nop.Plugin.ExchangeRate.EcbExchange.dll' is denied.

I have set permissions to the IIS user on the directory. When the application goes into error, restart the site from IIS and return to work. But after a couple of days the problem recurs.

I have a test site with a replicated database and no error occurs. I can not understand what the problem is. Can someone help me?

The application is installed on Windows Server 2012 Operating System and IIS Version 8.5.9600.16384.

Thanks in advance

Massimo

Hello,

May be this issue is related to Serious IIS Application Pool recycling.

Because, many developer facing this issue.

here you can find more about this issue and it's solution.

https://www.nopcommerce.com/boards/t/49851/serious-iis-application-pool-recycling-bugdesign-flaw.aspx?p=4#199793