RainbowMiner

That's weird. How about the Xmrig? Does this miner crash as well, or is it SrbminerMulti, only?

This looks like general connection problems. Is there any firewall or proxy involved?

Hint: if you had a previous internet outage, it may be that the RainbowMiner Cache is corrupted. Solve this like that: stop RainbowMiner, open folder "Cache" inside the RainbowMiner folder...

Yes, that is a known issue with that miner. RainbowMiner already does some magic to read the broken API, but the call to the API itself causes that error. I...