I recently encountered an error that is preventing MainWP from running on a specific child site. The plugin was working perfectly until recently. It may only be a correlation but I only noticed the issue after I tried to execute a snippet using the snippet extension.
The site became inaccessible so I assumed that it was MainWP related. I quickly deactivated the plugin through FTP and the site loaded immediately. I then deleted the old child plugin and installed/activated it from the repository. This time around, WP did not allow me to activate it due to the following error:
Parse error: syntax error, unexpected '<', expecting end of file in ..wp-content/plugins/mainwp-child/class/class-mainwp-utility.php(87) : eval()'d code on line 1
The site is running on the latest WP version of 5.7.2.
I tried to search the issue but looks like no one has reported this on the forums. Obvious conclusion is incompatibility however, because I noticed it after attempted to execute a snippet (Google analytics code), it could be associated with that.