My S7 never seemed to have a problem.  This used S9 I bought connects to
stratum.antpool.com:443  and  stratum.f2pool.com:3333

...just fine but reports stratum.kano.is:3333 (and a few other variations listed on the site) and some others as "dead"

I know they aren't dead since my S7 was working fine with them. 
Is this a known issue with the S9?  All I did was unplug the S7 and plug-in the S9 and enter pool data.

I don't know how to contact kano (which right now is my preferred pool) to ask...

THANK YOU!!
patricia