Bizhub 600 Fax Problem

[Brischaffer]

I have a Bizhub 600 that about every 2 weeks gets an incoming fax w/ no number and you can't delete it and it freezes the machine up. I have to take off the fax board and put it back in. Every other time it would work but today it didn't. Has anyone ever seen anything like this before?

Thanks,

Schaff