I have found myself a few times in the situation where a client reports an issue like ‘I can no longer login to my account‘.
Sure enough when trying to login with the client’s credentials myself everything works. After that, you start testing in other environments and situations, but still it works every time.
After numerous tests you start to wonder if the user is using the right credentials. Some clients get offended when asking this. Others are so sure that they enter the right credentials, they don’t even bother trying the credentials that you send them.
How can I make sure that the client is using the right credentials?
4
You can’t, because the user is already convinced that he/she is using the right credentials.
The best that you can do is to reset their account and inform them of their new password along with instructions on how to proceed.
If you have access to their ‘old’ password (which is a security risk of itself), then you could just send out a reply telling the user that you have ‘changed’ their password to that value and that they should use that password from now on.