Adding participants to many events

It sounds like you are experiencing an issue with Zendesk's live event management feature. When adding a collaborator to multiple events (spaces), they are receiving an email notification stating that they can only participate in one event at a time.

There are a few potential reasons why this might be happening. First, it's possible that Zendesk's system is designed to limit the number of events a single collaborator can participate in at any given time. This could be a technical limitation of the platform or a deliberate decision made by Zendesk's development team.

Another possibility is that the collaborator has accidentally accepted an invitation to participate in one event while they are already participating in another. If this is the case, they may need to decline one of the invitations in order to free up their availability.

To resolve this issue, I would recommend contacting Zendesk's customer support team for further assistance. They may be able to provide more information about why this limitation exists and offer suggestions for how to work around it. Additionally, they may be able to help troubleshoot any technical issues that are preventing your collaborator from participating in multiple events.