You dont get it less your solo mining it.

Just never seen an error before

Not sure if the error is cause your not using prohashing.com:3333#xnsub

I would leave the pool to set the difficulty

I think that with everything going on right now with NH shutting down and pretty much overloading every pool that is worth using had an effect on everyone so I would give it a few days to weeks to calm down from everyone panicing and pool hopping and over loading pools everywhere.