What it means if you see "Invitation pending" by a user's name

As a calendar administrator, you can add users to the calendar. To do this, go to Settings > Sharing. 

In the Sharing settings, you can also see a list of users. You may notice a red Invitation Pending label under the name of a user you've already added. 

This label means that the user has not activated their Teamup account.

When you add someone as a user, they will receive an email from Teamup. If the person doesn't have a Teamup account yet, the email will provide a link so they can activate their account. Then they'll be able to access the calendar.

If the red Invitation pending label is present, it means that they did not click the link and finish activating their account, and they cannot access the calendar yet.

You can re-send the invitation email: Click the Edit icon next to the user, then click Resend invitation. 

It's a good idea to notify the person that they'll be receiving the activation email. They may need to check their spam/junk folders. Some email clients automatically route emails to spam if the senders are not known contacts.