Sending mail from my own email server (a Cloud Server) to 365 hosted email accounts is suddenly refused this week. We followed all the steps 100 times (as described) but the e-mail is still refused with the message:
550 5.7.511 Access denied, banned sender[x.y.z.205]. To request removal from this list please forward this message to firstname.lastname@example.org. For more information please go to http://go.microsoft.com/fwlink/?LinkId=526653. AS(XXXX) [XXXXXXXXXXXX068.eop-NAM04.prod.protection.outlook.com] (in reply to RCPT TO command))
And we also tried the following two alternative methods 100 times each according to other Microsoft online documentation.
Use the Microsoft delist portal to remove from the blocked senders list.
The server is not listed on a blacklist (mxtoolbox check) and it is usual sending to Google hosted custom domains and other systems.
How can I delist my ip-address? And is it possible to see for what reason the ban is?
It's now day three with this problem and I want to know how to fix this. My clients are very unhappy.
Another Microsoft representative pointed me to post it to this community, I hopes it can be solved asap.