User Can't Sign In

Only one of the users on my forum has complained that when she logs in, she gets this message:
"You have specified an incorrect or inactive username, or an invalid password."

She has the correct username. It is not an inactive username. I changed the pw for her, it still didn't work. I tried logging in too, and it won't work for me either. Same message. As far as I can tell, all her settings are like any other user (nobody else is having a problem). What can we do?

Hello,

Can you please provide the link of your forum ?

Also, I'll need the username of this member (by PM if you prefer )

I apologize. She actually asked me to delete her account since she didn't want to wait for an answer. You can delete my post. Thank you so much!