Outlook mobile app duplicate meeting invitations

Copper Contributor

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.

3 Replies

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

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.



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