Caravan covers

Bigduke

Hi everyone,I have a cover for my caravan and I have noticed that the outside of the caravan is wet as in condensation,and the wooden cabinets inside are covered in what I think is a mould but it will come off on your fingers like a dust,is it the cover
not doing what it is supposed to do let it breath.If you have any thoughts on this I would be very happy to hear your thoughts.