New users were unable to accept an invite to a private tab and received an access denied screen.  This bug has been corrected, so you can resend the invite.   

Two ways to resend the invite:

1) Management > Members Menu

2) Click on the Avatar (picture) in the members list and select "Resend".

Please let us know if you run across any new bugs or just want to let us know what features you'd like to make tabUp more useful.