I've having the same issue with the Anitminer Z9 Mini and Nicehash.  It starts out with low reject rates, sometimes zero.  But over time it drops and drops until it fluctuates from 100% rejected to 80% rejected.  Reboot and the same thing happens.  I've tried different speeds - no difference.  I've tried pools in USA, EU, HK, Etc.  All work the same.

Did you figure it out? 
Did you give up and pick some other solution? 
What was it? 
Anyone else? 
I really just wanted instant bitcoin ... but I guess I may need to mine a particular coin.
Any good sites for Equihash mining profits besides whattomine?
Off the wall profitable coins?
Lots of questions (and frustration) - Thank you

So I used SMOS just because it was convenient. I had to create a bash script to kill the miners and keep them dead. Then it's just a pure manual process. The web interface is pretty much dead except I can tell if the rigs are on.

Create the file
touch killminers

Edit the file
sudoedit killminers

Paste this text and save.
#!/bin/bash
killall xterm -9
killall screen -9
screen -wipe
ps -efw | grep CRON  | grep -v grep | awk '{print $2}' | xargs kill
ps -efw | grep fanspeed  | grep -v grep | awk '{print $2}' | xargs kill
ps -efw | grep watchdog  | grep -v grep | awk '{print $2}' | xargs kill
ps -efw | grep update_status  | grep -v grep | awk '{print $2}' | xargs kill
ps -efw | grep emergency  | grep -v grep | awk '{print $2}' | xargs kill

Add execute to the file
chmod +x killminers

Execute the script
./killminers

If you have monitor on the rig then you will see some errors on the screen.
I was logged in as root for all of this so I logged as 'miner' and ran 'screen -wipe' and that cleared it up.

[/quote]

I used your instructions to accomplish the miner shutdown but ended with an error.  Could you explain why?  No directory was given so I put it in the root .. or so I believe .. don't know much about Linux.
----------------------------------
root@simpleminer:~# ./killminers
xterm: no process found
screen: no process found
No Sockets found in /var/run/screen/S-root.


Usage:
 kill [options] [...]

Options:
  [...]            send signal to every listed
 -, -s, --signal
                        specify the to be sent
 -l, --list=[]  list all signal names, or convert one to a name
 -L, --table            list all signal names in a nice table

 -h, --help     display this help and exit
 -V, --version  output version information and exit

For more details see kill(1).
root@simpleminer:~#
-------------------------------------------

Your help would be highly appreciated.  I have SMOS ... just not great with Linux - but can follow instructions.  By the way, the pool site has an ISO you can download for a Ubuntu Linux boot.  It comes to a MinerOS prompt with a login .. no idea what the login is.  Interesting.  http://mineros.cn/#/dashboard

The site seems to be working now - anything special to do for installing the miner ... youtube video you've seen in the past (obviously not this miner but a how to .. otherwise I can check .. just hoping you had a better resource than random looking around.

The link to http://uupool.cn/course/btm is not working - can you load it on some other site for download to help us out?  Thank you in advance

The pool has been going for a long time without a block found.
 Hashrate: 573.55 KH/sec
 Block found: about 14 hours ago
 Blocks found today: 0

Can you explain why?  Bad luck?  Thank you

I've joined the pool mining at 7700 H/S.  What is the /NoFeesForever requirement?

Thank you,
Vast