Just today my 2 Zmasters started showing 100% rejection rate on Nicehash and in the web interface, where they were close to 100% accepted before.  Both started doing it at the same time.  I tried switching servers, to no avail.  Tried resetting router, modem, and both Zmasters.  Is there a possibility it could be something not on my end, like Nicehash's failure, or should I upgrade the firmware with possibly no chance of going back to the old firmware since I can't find it on the internet?  I upgraded a Z9 Mini's firmware once and it disabled all overclocking options, so I don't want some similar ridiculous change.  It's strange that it seemed to be close to the time that Coinbase's addition of Zcash was announced, within a couple hours.  I'm not seeing any news on Nicehash.com or Reddit's Nicehash page that would give me a clue about the problem.  The miners are also getting up to around 20 or so Ksol/s (50 Ksol/s is what they should be at), or about 10 minutes of running, then going back down to zero and starting back up, while still showing 100% rejection, and both doing it at about the same time.  Both miners have the same firmware with the filename b29+_20180714_035505 from July 14.
Any help would be appreciated.