Here at AVPro Edge we take calls on a daily basis for issues with HDBaseT. Typically we find that the is no problem with the equipment, but rather an issue with cabling.
To help with this issue, HDBaseT has issued the 'Installers 10 Cable Commandments'.
A great read for any integrator, this document contains best practices for avoiding simple cable issues in your installations!
Proper CAT Cable Termination: