Troubleshooting 'Cannot Select INBOX, Is This a Valid Transport?' Error

Admins may encounter the following error when configuring support department mail importing via POP or as a notification email:

cannot select INBOX, is this a valid transport?

To fix this issue:

1. Click Edit at Configuration > System Settings > Support Departments.
2. Change Port from 993 to 995 .
3. Click Save Changes.

This will resolve the error.