what does this mean? "Value does not exist or does not match filter criteria."

I am working on the create a support process module on trailhead.  I am creating a case using 'Pat Stumuller' as the contact.  When trying to select I get this error "Value does not exist or does not match filter criteria".  I removed the name and get this when trying to complete

#Service Cloud. "We can't find a case associated with the contact 'Pat Stumuller'".  I tried creating a case with a different contact.  Same error.  I also tried to create new contacts with the same error.