Could someone please tell me wy i get this error with silentarmy version?

Hash tables will use 1744.8 MB
threads: 8192, work size: 256
Connecting to frontend: coinsforall.io:6668 ...
ERROR: invalid hostname and/or port.

zcashgpuclient_silentarmy.exe doesn't work while zcashgpuclient.exe works..