Porblems with a user login

[Jasper Bohm]

A user contacted me with the following error:

Email, has no access to Jira on our atlassian.net site.

So when checking the user status, he does have access, although the email he was registered with no longer exists. So we've recreated that as an alias to his existing email. But this doesn't explain the deny of access. So I suggested using the old email as a login name, which still resulted in the same error. Then I actively denied the access to the site and turned it back on. I also used the admin panel to suggest changes to his account by suggesting the right email address. We've also send multiple password resets which don't end up in the users mailbox. We've tested the alias and that works.

So my question is basically, how can I edit my users access to the site without the user's interference? Like changing the users email address and resetting the password manually?

Or is there any other method to give the user access to the site again?

Thanks in advance.