If you are using Teams for your custom event it is important to get the correct link when sharing your event. You may copy the link from the following two locations.
WARNING: Copying the Teams meeting link from locations other than specified below may result in an incorrect link being shared and your users will be unable to access the event.
Correct Locations to Copy the Teams Meeting Link
1. From the calendar section of your Teams app, navigate to the Teams meeting you've created for your event. Click once on the event.
2. In the pop up, click on the copy button next to the URL to copy the link.
3. Alternatively, you can also open the event by double-clicking the calendar event and clicking the Copy Link button at the top under the Event Title.
4. Add the link to a session, see the Custom Event - Create Session(s) article.