Unable to access Win10 profiles on desktop machine

[Windows Central Question]

I have multiple profiles set up on my Win10 and they have worked flawlessly for over a year, but now one of the family users cannot log onto her profile. The thinking dot circle goes round and round then a dialogue box pops up saying the administrator needs to sort out the issue. I am the administrator (I think) as I set up Win10. I would like to restore my family member's access to her profile. How?