If you are attempting to connect EAP to your apple mail folders on Mojave you will need to manually grant EAP ‘Full Disk Access’ permission on Mojave. This is a new security feature introduced in Mojave.
You can do this by doing the following:
Settings (your apple settings)-> Security & Privacy ->
Full Disk Access
Then add Email Archiver Pro as a supported App.
This should give EAP access to mail.apps v6 folder.
Quit EAP and restart it again.