I keep getting SMTP errors like: 334 VXNlcm5hbWU6 UGFzc3dvcmQ6 Authentication unsuccessful [BL1PR13CA0304.namprd13.prod.outlook.com 2026-01-22T20:59:23.476Z 08DE59C2EA6C3D25]
and: '550 (x.x) [x.x.x.x]:xxxx is currently not permitted to relay through this server. Perhaps you have not logged into the pop/imap server in the last 30 minutes or do not have SMTP Authentication turned on in your email client.'
See also:
https://news.ycombinator.com/item?id=46724812
https://news.ycombinator.com/item?id=46724544
https://www.reddit.com/r/msp/comments/1qk45c0/microsoft_serv...
https://www.reddit.com/r/sysadmin/comments/1qk3tg7/microsoft...
https://www.reddit.com/r/sysadmin/comments/1qk518l/email_ser...