https://www.reddit.com/r/sysadmin/comments/1iu0x33/anyone_else_seeing_ptr_record_issues_with_m365/
Yes you do need a ptr. The big services will outright block you.
https://www.reddit.com/r/sysadmin/comments/1iu0x33/anyone_else_seeing_ptr_record_issues_with_m365/
Yes you do need a ptr. The big services will outright block you.