Forum Discussion
Lot of eventID 4999 related to ActiveSync on my Exchange Servers
BroBias Interesting that you also have a firewall/loadbalancer in the mix as well and think it's part of the issue. We don't have Sophos. We have Fortinet on the perimeter and then a Kemp loadbalancer internally, I think at one point I stumbled upon someone mentioning the session timeouts may be the culprit but I never found the right values to prevent the errors either. Sure would be nice if somoene on the Microsoft side would chime in on these annoying errors.
Yes, I'm also 99% sure that this relates to the combination of EXCH vdir <> FW/LB <> ActiveSync requests/sessions. I can even find this reflecting in the event logs, when the errors starting as soon as the users are off to the weekend or coming back from weekend again. I also played a lot with the http session timeout setting on fw/waf side but without any success, not even little changes in the amount of logged errors.
Even following very clear recommendations for EXCH + SophosXG - no effect at all.
The main issue is, from my perspective, that these errors don't cause significant issues, at least not on my side. From time to time some few users complain about "sync hangs" on their mobiles but that's it. Exchange seems to be fine whith recycling the app pool every hour ......
However, i'm annoyed about it because it's just filling up my event logs and leaves a bad feeling while not really knowing what's going on.
Hi BroBias7 and cmillerLCE ,
Sorry for the late answer but I have to admit that did not take this error in account because ActuveSync is just working fine.
On our end, we also use a load-balancer (F5 Big-IP) so it is probably something to investigate deeper ... or not.
On my side I decided to stop my investigation.
Good luck guys !
- Running Exchange 2019 three node DAG with FG Big-IP LB.
Same issue here ... no progress on it though.
