If you are using Microsoft Exchange account I will suggest to go with the Microsoft Default setup.
If you gonna use a regular mail in email account you need to setup OAuth2.0 for the mail account, then create a password for mail there and use that password.
And I suggest for both cases try a user ID which has the access of the mail ID.
For your clarity, I got the same issue. Client told me make a email account as standard for remittance mails. I worked around a days for the same issue. After that I got the solution and ask the admin to create a shared mailbox and provide me the access too for testing purpose. And that worked for me.
If my answer helped you, maybe it can help others, please verify it, so other users know it worked. Thank you.