Why did you assume that it's your router blocking Braiins OS? it doesn't make sense, if it does -- it would likely block the main pool you using as well, which also explains why the miner did not operate fine with the default firmware
I could'nt even acces the miner with the standard login of brain os wich is root.
After reset i could login again.
This is bad news then, the miner could be infected with a nightswitcher or some other type of miner virus, otherwise, I see no connection between connecting to the pool and connecting to the miner locally, you also said you have another miner running which means we know neither your router nor ISP is blocking pool connections, so it's likely an issue with the mienr itself.
I would revert back to the original firmware, and use custom DNS like Max suggested, and then troubleshoot form there.. keep in mind if your miner is indeed infected it could inject the other miner you have running so make sure you isolate it for now.
