Outlook mobile app duplicate meeting invitations

[leszeknt]

Outlook app on mobile devices (both Apple and Android) sends duplicate meeting invitations every time, every user. I cannot find the reason. It started to happen recently. I have duplicate items in "Sent" and recipient gets duplicate messages, and there are duplicate calendar entries. Messages headers differ: one has message id ending with "namprd06.prod.outlook.com" and the other with my domain name. Other apps do not have this problem like iPhone native Calendar app sends invitations correctly. I use Exchange 2016 CU20 Version 15.1 (Build 2242.4). Planning to upgrade to latest soon.

[#2]

@leszeknt We have the same problem. Did you ever solve this issue?

[#3]

Hi all, same problem here. Anyone?

I tried: Outlook Mobile iOS/Android on both Exchange 2016 and 2019, but all migrating from previous versions. Even asked to some other friends that manages Exchange environments: same result!

Same Outlook Mobile app with an Exchange 2010 or 2013 is ok.

Any other mail app seems to be working fine, the issue seems only with Outlook Mobile.

Thanks!

[#4]

@leszeknt I have the same issue.  Did you ever get any resolution to this problem?