There appears to be an issue with the DotRes US POS. Selecting a different POS (e.g. UK) will resolve the issue for now.
The only other option I have is to select Fares/TVN, but these listings are limited and do not cover the fare listings thoroughly like Fares/ DotRes. How do I connect to a Fares/DotRes UK server? Is there a way for you to notify Sabre to fix the US based problem?