Also, in the past we sent out some emails to real estate professionals that automatically logged them into their accounts. We explicitly stated that these emails should not be forwarded, but that didn't stop many from doing so in any case We discontinued those emails several months ago because of this.
My best guess is that one of these issues is to blame. Let us know if you have any more information that might shed more light on the situation. You can feel free to email me directly and I'll forward that information to the appropriate parties that can help.