Invite users to this tenant is not updating

I have invited to people to the tenant to be dashboard admins;

mclark@n-focus.com
jbieber@n-focus.com

mclark received the email and followed the link to get access and was told it was successful.

Now his name is no longer in the list of those that have been invited only jbieber remains.

mclark also does not see the tenant when he logs into the auth0 site admin when selecting switch tenant.

It seems like it has just disappeared. What should we do?

I just performed an invite flow for one of my tenants/domains and after completing it successfully I was both able to use the tenant switcher to select that account and the original admin was also now able to see that the invitation no longer listed as pending and an additional admin is listed.

The recommendation would be for the invitation flow to be repeated; if the issue persists it may be useful to do it again and capture the steps taken so that you can include more information in the question in order to help troubleshooting.