An exception occurred while establishing a connection to figure out your platform version.You can circumvent this by setting a 'server_version' configuration value . I got that error . My App is on a diffrent server and my database is on AWS RDS. I have configured the database on my host with the right group access and confirm via SHH that my server is connecting to the database .
That usually means your production environment connection info is incorrect, read Setting Production Connection Info.