Overview
What to do when the admin wants to link a new user in the Synchronizer and the admin cannot choose any users from the external calendar pull-down listthere are no pull down lists.
You will also see a the notification on the top of the screen in the Link Users page that an error has occurred while connecting that the Synchronizer is unable to connect to the external calendar system.
What it means is that the password of the external calendar system in the profile is expired.
How to
To fix the expired password click in the message on Check your configuration here. This on the Fix Your Connection Here button. This will bring you to the Configure systems page and here where you can fill in the correct Exchange password. Or if you are using re-enter the password by clicking on Sign in with Microsoft for Microsoft 365 or Google click the Connect(ed) button to log in Sign in With Google for Google Workspace.
Don't forget to Save!
Now you can return to the Link Users page and link new users.