added users cannot log in!

added users cannot log in!

Would appreciate any advice ..
 
I added a second user to my zoho mail account, assigned the email ID & password.  If I sign out as the primary administrator, and try to log into zoho mail using the email ID and password fro the second user, zoho just shows "page not found".
 
The primary user works fine, I have no idea what step I've missed.  Have tried deleting the user and adding again, same result.
 
thanks!