Unable to save any system configuration settings
I've run into a problem where I can't make any changes in Advanced settings. At present, I'm trying to configure the SMTP server setttings, but I'm finding that even though I can change the settings and I get a message saying "Settings Successfully Saved", the moment I navigate back to the settings I just changed, I find it really didn't change.
I'm currently using SiteFinity 4.2. The live production website is having the problem, but the local development copy is not.
Make sure you have granted your app pool identity the necessary read / write permission on App_Data folder. If this is not set properly, Sitefinity will not be able to make any modification to your config files (which could explain why you cannot modify the settings)
Here is our official documentation: