Unable to set co-organiser on a specific teams meeting

Dear @Hugo White,

Thank you for reaching out to Microsoft Q&A forum.

I understand you're experiencing an unexpected issue with a specific Teams meeting. From your description, it seems that the underlying metadata for this particular meeting invitation has likely hit a "corruption limit" or entered a synchronization loop within the Exchange calendar. As a result, while the interface allows you to select a co-organizer, the "save" command is being rejected by the server, causing the list to revert to a blank state each time you exit.

Since this is happening with only one meeting, it appears to be tied to the specific meeting ID, rather than a global setting. Recreating the Teams meeting is probably the easiest solution.

Please try these steps to see if they help:

1. Have the organizer go to Outlook on the Web (not the desktop app).
2. Open the calendar, select your meeting
3. Go to Options and try adding the co-organizers there.

If the bot account is "stuck" in a corrupted state:

1. Open the meeting invite and completely remove the bot account from the attendee list.
2. Send the update
3. Wait 5 minutes, then re-add the bot account
4. Send the update again.
5. Now, try to assign it as a co-organizer in Meeting Options.

Toggling a different security setting can sometimes "wake up" the save function:

1. Go to Meeting Options.
2. Change "Who can bypass the lobby" to a different setting (e.g., from "Everyone" to "People in my org").
3. Add your co-organizer.
4. Hit Save. If it sticks, you can then change the lobby setting back.

Additionally, I recommend that the Global Admin in your organization create a service request with Microsoft Support. A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to provide a targeted solution. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis. Ask The Global Admin in your organization to create a service request with Microsoft support to get advanced technical assistance and diagnostics. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin. If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

I hope this information helps clarify the situation and provides you with effective solutions. If you have any further questions or need additional assistance, please don’t hesitate to reach out. I’m always here to help. Have a wonderful day!

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Documented behavior for co-organizers in Teams focuses on how to configure them and what they can do; it does not describe a supported way to repair a single recurring meeting where the co-organizer list will not persist. The symptoms described (co-organizer can be selected, Apply works, but the list is empty when reopening Meeting options, and only for one long‑running series) are not covered as a configurable setting.

From the available documentation, the relevant constraints and behaviors are:

1. Co-organizer requirements
   • Co-organizers must be invited to the meeting as attendees first.
   • They must be in the same organization as the organizer, or use a guest account in the same org.
   • External participants cannot be made co-organizers.
   • There can only be one organizer; that role cannot be changed.
2. How co-organizers are set
   • In the Teams calendar, open the event and go to Meeting options.
   • Under Roles → Choose co-organizers, search for and select the people to promote.
   • Select Save (or Apply in the new Meeting options UI).
   • Co-organizers then appear as organizers in the participant list and have nearly the same permissions as the organizer (manage breakout rooms, change meeting options, end meeting for all, etc.).
3. Behavior in recurring meetings
   • For recurring meetings, role changes made in Meeting options apply to all future occurrences of the series.
   • Role changes made during a single occurrence (via the People panel → More options → Make a presenter / Make an attendee) affect only that occurrence.
   • Co-organizers cannot change the meeting before it starts; only the organizer can set roles in advance.

Given that:

• Co-organizer assignment works correctly for other meetings in the environment.
• The affected meeting is a recurring series that has been modified multiple times.
• The organizer can select the bot account and apply, but the selection is not persisted when reopening Meeting options.

The available documentation does not provide any supported remediation steps for “resetting” or “repairing” a single meeting series whose Meeting options appear to be corrupted. The only documented, reliable way to ensure that co-organizer configuration is stored and behaves consistently is to create a new meeting (or new recurring series) and configure co-organizers there.

A practical approach, based on the documented behavior, is:

1. Create a new recurring meeting in the Teams calendar.
2. Add the bot account and any other required co-organizers as required attendees.
3. Open Meeting options → Roles and configure Choose co-organizers for the bot and any other co-organizers, then select Save/Apply.
4. Copy the attendee list and meeting details from the old series into the new one and send the new invite.
5. Cancel the old series so that all participants move to the new meeting and the bot can reliably access attendance reports going forward.

The documentation does not describe any alternative method (such as a per-meeting reset or repair) that would fix the described behavior without recreating the meeting.

References:

• Add co-organizers to a meeting in Microsoft Teams
• Roles in Microsoft Teams meetings
• Teams controls