I have tried configuring a regular user and a shared mailbox. I can't connect a custom email account to either. I can log in via outlook.office365.com using the same credentials without issue.
I tried with Microsoft as the provider and other using IMAPS.
Unfortunately JIRA couldn't connect to the mail server. Here is what the mail server said: "AUTHENTICATE failed."
This worked fine in the classic projects, but not in the next-gen service desk.
I'll also clarify that 2FA is enabled and I've created an app password. I tried using that, but the error is still the same whether I try and connect via Microsoft or IMAPS
