I would suggest taking your coach to a commercial propane dealer (one that can re-certify even though a coach mounted tank does not need it), so they can check your RV propane tank out and resolve your problem safely. You paid a lot for your coach; you don't want to scrimp a few bucks for a proper fix and have it or its irreplaceable contents (you or family) burn up. There is lots of info on line about this kind of trouble (I am sure you are already finding it):
Propane tank won't fill - Winnebago Owners Online Community
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