Update 3/31/2026: This change has now been fully rolled out. If your EWS applications have access problems, please verify your tenant and mailbox level EWS settings.
In our ongoing commitment to en...
Updated Apr 01, 2026
Version 5.0
Blog Post
As all of my Teams calendars stopped syncing with Exchange online over the weekend it looks like you broke my setup. Gosh thanks for nothing, no bulletins except for this one. I am going to set org enabled to true to see if I can fix what your change without adequate notice broke.
Thanks for killing my week.
- Greg Taylor - EXCHANGE
Microsoft
Hey Jim - sorry you got caught out by this - you should have had the Message Center posts too though, which are the official way we communicate changes like this. I know we send a lot of stuff there, but keeping an eye on that is really advisable.
Again, sorry for the outage, hope you got things going again before too long.
One question though - modern Teams clients don't use EWS to show the Exchange Online calendar. What's your configuration/versions if this truly was the issue? Are these on-prem mailboxes?
Hmm,I looked at service health and didn't see this one.
Exchange-online
Teams-online
This started last weekend (or a bit before) Org behavior is set to false which surprised me. Sadly L1 support has been most unhelpful on analysis so I'm essentially left to research on my own.
My plan is to turn the org default to true and see "if" that fixes it. If it does not I'm not a happy camper since I'm getting no help from MS support and your KB article seems to fit. I've made no changes to our environment and this (to me) came out of nowhere!
The issue shows up on locally installed Teams/Outlook and the portal.office.com (web versions) no change.
I'm still telling level 1 support CLOSE THE TICKET. I added some ,I've solved it independently of "your" support. Level 1 support (and I rarely say this quite so directly) in this instance was useless. They had zero idea of the EWS issue and troubleshooting consisted of workstation level steps. I mentioned "how about EWS" and got crickets chirping and continued "send support x,y,z info that I'd already sent them.
THIS WAS NOT communicated well. I went back through bulletins and found nothing. In other instances MS has sent us alerts saying "we still see X ON after specific date it won't work you might WANT to update your tenant setup.
Greg, if you're still here, thank you for your help but I'd vigorously disagree with you that this was communicated effectively.
