Plugins error: nopCommerce needs to be restarted due to a configuration change, but was unable to do so.

I'm running NOP 4.00 on IIS (my own server) and have the correct permissions set (as per the WARNINGS section in the Administration)for all files and folders, however, when attempting to install any plugins, I get the following error:

nopCommerce needs to be restarted due to a configuration change, but was unable to do so. To prevent this issue in the future, a change to the web server configuration is required: - run the application in a full trust environment, or - give the application write access to the 'web.config' file. 

I also have IIS_IUSRS and IUSR with modify on the web.config file. - still no joy.


What other settings and permissions are required? And for what files? I'm new to DotNetCore, so I figured there were other settings to make this work properly. I thought Dotnet Core was always full trust - where do you make these changes?