If you are an Outlook 2019 or 365 user whose account is configured using the POP or IMAP protocol, you’d just need to follow the below instructions to delete your account and re-add it as an Exchange account. In that case, SSD users should please contact SSCS for help. If the OS/app combo does not support modern authentication, then you will need to find a combo that does. Outlook for Mac – Office 365 (exchange only, no POP or IMAP)

Outlook 2019 for Mac (exchange only, no POP or IMAP) Windows 10 Mail (exchange only, no POP or IMAP) Outlook – Office 365 (exchange only, no POP or IMAP) Outlook 2019 (exchange only, no POP or IMAP) Outlook 2016 (exchange only, no POP or IMAP) While these protocols are capable of using modern authentication, in your case they are not currently configured to do so since your email client app was originally set up to use basic authentication. IMAP, POP, Authenticated SMTP: These older email retrieval and sending protocols are used by a wide range of email programs on Windows PCs, macs, and mobile devices.

This guide is aimed at users employing Thunderbird or other non-Apple, non-Microsoft mail programs.

Gmail imap settings thunderbird