Coursepress Pro plugin conflict not allowing to establish database connection

I cannot access my webapp, sending error "Cannot establish database connection" or 503 Error 503 Backend fetch failed.

If I deactivate the plugin (Coursepress) the site is able to load. Once is activated site doesn't work.

Also the plugin keeps showing alert to update it to version1.3.4.3 (currently showing version 1.2.6.7) But when i try to update is shows a message sayin i have the latest version of the plugin.

Any help on how to fix this will be greatly appreciated.