Getting an unknown error when trying to add a user to the portal.

Getting an unknown error when trying to add a user to the portal.

I am trying to add a user to the portal.  I get this error message "An error has occurred. Please contact support@zohocreator.com for assistance."  I have sent an email to support, but I am curious if anybody else has seen this message and knows what it means.  I have attached a screen shot.  I am stuck until support gets back to me, so if anybody knows what it means let me know.