Email not Attached to Form
It takes a couple minutes for RPM to scan the email inbox and match emails to forms. If there is a complaint that an email is not attached, in Setup >> Email integration, check the Activity box to see when the Last check was.
Matching Test
If emails are not matching to forms, check the email subject line and view the result.
This tool is located in Setup >> Email integration.
Setup History
If things are not working, it is best practice to check the Setup history, which shows all the changes made to the configuration of Email integration and who did them.
Setup history is located in Setup >> Email integration >> Setup history.