Unable to unlock an object

Good day,

I hope someone will be able to help.  We have a user that is trying to open a model, but gets an error that the model is locked.  User in message is the same user trying to open the model.  We tried unlock and admin-unlock and it is not working.  How will I get the models unlocked?  User don't have any other sessions open, and also tried to log-out.

Working on ARIS version 10.0.4.1223502

Thank you in advance

Annelize