https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-deprecation-in-exchange-online-time-s-up/ba-p/3695312
Application developers who have built apps that send, read, or otherwise process email using these protocols will be able to keep the same protocol, but need to implement secure, Modern authentication experiences for their users. This functionality is built on top of Microsoft Identity platform v2.0 and supports access to Microsoft 365 email accounts.
If your in-house application needs to access IMAP, POP and SMTP AUTH protocols in Exchange Online, follow these step-by-step instructions to implement OAuth 2.0 authentication: Authenticate an IMAP, POP, or SMTP connection using OAuth. Additionally, use this PowerShell script Get-IMAPAccesstoken.ps1 to test IMAP access after your OAuth enablement on your own in a simple way including the shared mailbox use case. If this is successful, just make a confident next step talk to your application owner of your vendor or internal business partner.
https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online
Not sure if this is relevant but it could be why pop3 isn’t working and giving me the username/password error cause of the changes, but regardless of it being office or google it just doesn’t work 😞