If you see a CH has rated every single entry as a no thank you, post a positive public message to them asking them for new directions, affirming that we are still going to work on their contest, etc.
IF you don't receive feedback soon after posting the above, use the blue bubble to let SH know that the contest is on the skids so they can reach out to the CH!
Realize that the CHs OFTEN don't understand how the system works, especially in terms of what names might be feasible with what domain extensions. Kindly ask them if they would consider broadening their scope.
Please, I beg you, stop asking CHs if it is OK to withdraw unrated names "because creatives have a limit"! It just really doesn't sound great, to be honest, especially when that is the only message on the board! And CHs have no idea what you are talking about! I think it is OK to ask if they are still considering unrated names...just not that other part.
There are only a very small handful of creatives who actually post questions to the CHs. I know why that is and I understand it... but it would be nice if a few more creatives did.
I also want to "echo" what @hollygirl said about names in the brief AND previous winning names. It just doesn't look good for all of us.
If a CH is frustrated and posts something frustrating, report it to SH before going and hitting send on a negative response. OR, say something nice.