Participants disconnect after 90 minutes

There is an issue where non-Skype for Business participants will drop from a Skype for Business meeting after exactly 90 minutes. This is due to the Microsoft settings. For example, Skype for Business server has a setting which controls how long anonymous users are allowed in a meeting.

The setting is AnonymousUserGracePeriod and the default value is 90 minutes.

You can check the value with this shell command:

Get-CsUserServicesConfiguration

For more information, refer to Microsoft documentation.