I have enormous numbers of "stratum requested work restart" messages one after another, without a single accepted share, on all my miners CPU, VGA and even Gridseed 5 Orb, and here are they even reported as offline (because they did not find a single share)
My case is similar today.
Current speed of my workers is reported as 0.0 kH/s instead of about 500 MH/s.
They are connected to litecoinpool and work as usual, just the speed displayed at the site is zero.
What can be a cause of it?