How the hell do you build a user experience for people who are maliciously ignorant about computers?

I have a client with two employees who *refuse to remember their usernames and passwords* and I get emails at least once a month saying "employee 1 can no longer access the portal."

"Why not?" I ask.

"Not sure," with a screenshot saying they input the wrong username/password.

So I have to log in, reset their password and send it to them. I've tried forcing them to set their own password...