Unable to accept Invite

Hello, I have a new employee that is replacing someone at our company. We use Google Apps for email and I renamed the user who is leaving to the new person's name. The new person's login is their own name however when I send an invite to the new user to join Zoho CRM and they click on the link, it says "the old user names" does not exist.

Everything on the user side of Google apps reflects the new username however, for whatever reason, Zoho is still recognizing the old username and won't allow them to accept the invite.

Is there a way around this?