So is it possible that for example stratum+tcp://stratum.nicehash.com:3333 which is a port for scrypt algo works, but 4333 does not work?
Yes of course, 3xxx pools are always online.
But 4xxx pools are only online when they are most profitable, so multi-algo configuration must include(ideally) all 4xxx pools.
hmm. there might be some different problem here right now... I have now switched back from 4xxx pools to 3xxxx and I see X11 and X13 pools are dead (scrypt, scrypt n-factor and keccak are alive). and from what I see, X11 is now the most profitable and that might be the reason why I'm getting all pools dead with autoswitch.
Do X11 and X13 nicehash pools work for anyone right now?