EXO or on-prem? We see a lot of authentication errors and sync issues, so much so that we block the "Apple Internet Accounts" EA since it stops the users from a

EXO or on-prem? We see a lot of authentication errors and sync issues, so much so that we block the "Apple Internet Accounts" EA since it stops the users from adding it in the first place on tenants we manage. One particular well documented issue that first cropped up about 5 years ago that I still see to this day is the spam of calendar invite acceptance e-mails (so much spam that the user gets outbound blocked). Only happens if the user accepts a calendar invite using the iOS calendar client, MS couldn't identify an issue and Apple didn't wanna hear about it.