Duplicate Invitations sent when entering Meeting on Android Device

One more information:

One invitation contains the information "Outlook Internal version", the other does not.

My understanding is that when the sender check the meeting item in the Outlook for Android application and Outlook on the laptop, there is no duplicate meeting evens, and the duplicate meeting events only existing in another third party Calendar APP on the Android, right? 

If so, to troubleshoot this issue, please remove/disconnect your office account from all other mail/calendar apps on your Android or all other devices, and then only use Outlook for Android APP to create and send a meeting invite email to see if there is the same result. 

2. "The two meetings created in the recipients's calendar are slightly different" and "The two invitations are slightly different".

The recipient received two invitation emails, so there are two calendar events on their calendar, right? If so, if the recipients are using an office 365 for Business account, please let the recipients login to Outlook web app to see if there is any difference.

3. "both invitations were visible in Outlook on the laptop but not on the Android device.”

Do you mean that the recipient can see both invitations in Outlook on the laptop but not on Android device? Or does the sender see the invitation in Outlook on the laptop but not on the Android device? 

Please kindly check if the sender/recipient can see the duplicate invitations in the Sent Items/Inbox folder in the Outlook for Android APP.

Moreover, to further investigate this issue, please contact your admin to run a messages trace to trace for the duplicate invitations and export the trace result to a .csv file, then share this .csv file with us in the Private Messages (PM) for further analysis. Here is the link to the PM: 

https://answers.microsoft.com/en-us/privatemessage 

Thanks for your understanding and cooperation.

Regards,

Jennifer

HI Jennifer,

1. the sender only sees one meeting, regardless of the client.

The recipients get two invitations and therefore see two meetings, regardless of the client.

There is no difference between Android Client, Outlook and OWA, because the recipient gets two invitations (which I see in my sent folder), therefore there are two meetings in the recipients' calendar.

2. no difference in OWA

3. no

what I wanted to explain:

When I stopped synchronisation of emails (but not of the calendar) the meeting was transferred to the server, two invitations were created in the sent folder and the recipients got to meetings.

On my Android client I did not see the to sent invitations unless i sychonized emails again.

This was only to show, that the invitations were not created at the side of the Android client but on server-side.

I will ask the administrator for the message trace.

Regards

Peter.

Hi Peter,

Many thanks for your prompt reply and let us know above information. After analysis the information you shared, the duplicate invitation seems to be sent from another user's email address. To further investigate this issue, please contact your admin to run following PowerShell command and share the result with us at the PM:

1. Contact to Exchange online PowerShell.

2. Run following command: 

 Get-mailbox | fl identity, servername

Meanwhile, may I confirm whether the problematic users have set a delegate for his mailbox? 

Thanks for your understanding and cooperation.

Best regards,

Jennifer

Hi Jennifer,

I will ask him on Monday and send you the information.

I found the "delegate" as an issue when searching for a solution and checked in my Outlook-Client.

There are no delegates shown there and I never used this feature.

Regards

Peter

This is what it looks like

Hi Peter,

Many thanks for your prompt reply in the PM, I checked the result you shared but didn't find any related information about the "other sender".

However, as you mentioned you doesn't have this issue when sending invitation to the user "KL", could you please share the message header of the email that has no such problem with us in the PM so we can compare it with the previous one? 

In addition, as the specific situation is still not clearly, to further narrow down this issue, I‘d like to confirm following questions with you:

1. Do your organization using pure Exchange online server or has a Hybrid deployment?

2. Regarding "the sender only sees one meeting, regardless of the client", please clarify will this problem occur in the following situations:

• Does this issue happen if you use Outlook web app send meeting invitation emails?
• Does this issue happen if you use Outlook desktop client send meeting invitation emails?
• Does this issue happen if you use Outlook for Android APP send meeting invitation emails?
• Or is this issue only happening when using third party apps in the Android device

3. Also, please clarify if there is only one invitation email in your Sent items folder when this issue happens. 

Moreover, I will send two test accounts to you in the PM, please kindly sign in to one of the test accounts in the Outlook web APP and send meeting invitation to the another one to check the result. Similarly, you can test this issue in Outlook desktop client and the Outlook for Android APP. 

Thank you very much for your understanding and cooperation, looking forward to your reply.

Best regards,

Jennifer

Hi Jennifer,

To answer your question:

1. It is pure online server, no hybrid deployment
2. The issue only happens when using third party apps on the Android device (regardless what app I use, I tried three of them). Outlook App, OWA and Outlook on Windows 10 work fine.
3. There are two invitations in the sent folder. As I pointed out, these invitations are created on the server side, not at the client side. I tested this by enabling and disabling synchronization of meetings and mails.

Can you see at your test account, if the Android client sent two meeting requests to the server?

I used the test account with last digits 532 and the same thing happens, wenn I add the meeting on Android.
You can see the two invitations in the folder sent. Subject it "Testeinladung Nummer 1"

I created a meeting in OWA. You can see one invitation in the folder sent. Subject is "Testeinladung Nummer 3".

Regards
Peter.

Hi Peter,

Thank you for your prompt reply and let us know above information.

As this issue doesn't happens in OWA, Outlook desktop client, Outlook for Android APP, it means that our server is ok and it seems that this issue is related with the third party APPs. Given this situation, I would like to suggest you please contact the third party APPs support team to further confirm and work this issue on their side.

Also, please let us know how do you configure your account in the third party APP. In the meantime, I will also consult this issue with our senior engineers, I will post back if there is any update on our side as soon as possible, looking forward to your understanding.

Best regards,

Jennifer 

Hi Peter,

I would like to know how the entire thing goes on, have this problem been solve now?

Regards,

Shawn