Webinar Attendee Shows They are a Participant but is Not Accessing the Webinar

We do multiple webinars every month.  Attendees have to register and then use their link to access the webinar.  I have an attendee who shows they are in attendance but they are not able to access the webinar.  They can’t use the link again because it says they are already an attendee.  If I remove them, it says they won’t be able to rejoin.  This has happened to this attendee more than once.  Any ideas on how to resolve this?