“Teams” were SugarCRM Pro features, if I’m not mistaken.
I think that Group Emails should work in SuiteCRM, though these configurations are always a bit fragile. I would recommend trying things out with a really simple email account, nothing Gmail or Hotmail or Azure, nothing OAuth or whatever. Just plain user/password account. I use gmx.com emails for all my tests.
Another thing that you might want to check is how things are saved in the DB. Double-check everything in inbound_email, outbound_email, including the fields that are Base64 encoded.
Finally, you can step through the inbound email process with a debugger to see exactly how/why it’s failing to get the email. Start here: https://github.com/salesagility/SuiteCRM/blob/master/modules/Schedulers/_AddJobsHere.php#L560
(you want function pollMonitoredInboxesAOP, don’t confuse it with pollMonitoredInboxes which is the old version)