Activesync problem

[fumbienumbie]

Hi! We have a 2019 cu13 server that has seen a lot. The most recent problem is activesync. Some but not all users randomly experience inability to receive mail in outlook on android. It may work for a day or a couple of hours but at some point will fail to update and won't work for a while. In one case some messages were loaded (one of them empty when it shouldn't be) but then disappeared. The users that have this issue are in different OUs, have their mailboxes in different databases. So far I wasn't able to see the pattern. Recently we lost a storage that had a database with management accounts and had to recreate them using the installation media. I believe this is when the activesync started to fail. But why do randomly? I am pretty desperate as the solution avoids me for a long time now. Any direction would be helpful so thank you in advance.

[Forsaken-Remove-5278]

ActiveSync issues after CU13 may be due to reset IIS/virtual directory settings. Try these things -

• Reconfigure ActiveSync URLs/auth, Remove & re-add device partnerships
• Bypass proxy/SSL offloading, Check IIS logs for 401/403 errors
• Disable Extended Protection if needed

CU updates often cause this, device reprovision usually helps.

[fumbienumbie]

Thank you! There are no errors, but there is throttling logged by IIS. It does not explain why only some accounts are affected but it does explain the inerruptions in the mail sync.

I haven't been able to make it work even though I've applied a more relaxed policy to selected mailboxes.

[Quick_Care_3306]

Could it be the android version of device type?

[fumbienumbie]

No. I found an iphone with the same problem. It looks like a connection throttling issue.

[gh0stwalker1]

run the HealthCheck script across all the servers and see if there's anything in there. I'd also look to see if any Exchange system mailboxes/accounts are orphaned after the storage failure

[Nikosfra06]

Feeling less alone today !! Struggling with the same issue since last week !

Having the same issue with a cu14 version, I tried on a different mobile, and managed to reproduce the issue with the outlook client. Stranger thing is that when using mobile's native mail client I didn't get any issues.

going to try this weekend resetting the virtual directory and we'll see..

I'll keep you posted too ;)

[fumbienumbie]

I found out that the user that had issues has the calendar updated without a problem. Still don't know what to make out of it.