Microsoft – incompetent or malicious?

A couple of days before christmas, mail sent from my mail server to people hosting their mail in the MS Office365 platform started bouncing: <NN@xyz.no>: host xyz-no.mail.protection.outlook.com[104.47.18.74] said: 550 5.7.511 Access denied, banned sender[X.X.X.X]. To request removal from this list please forward this message to delist@messaging.microsoft.com. For more information please go to http://go.microsoft.com/fwlink/?LinkId=526653. AS(1410) [AM6EUR05FT044.eop-eur05.prod.protection.outlook.com]… Fortsett å lese Microsoft – incompetent or malicious?