Changing email addresses caused issues

I am helping one of my programmers change the email address on his account.

He was using his personal email address and I want him to use his company email address.

To make the change e first created a new gitlab account with his company email address, but that would lose all his history.

So I just had him change the email address on his existing account and delete the new account.

But now he can not access any of the projects. He get a 404 error on the pages.

Also, even tho he deleted the new account I still see that account when I search for him by email address.

How can we get rid of the new account so it does not show up in search?

How can we solve the 404 errors? He did clear his browser cache.