Tester agents on LAN farm not working


Dear fellows

please give me a hint for solution of my problem:

Metatrader 5 , build 3621, LAN with tester agents.

Agents are set-up, updated with new file from MT5 install. Agents are visible and ready - please see screenshoots attached.

Problem is that LAN agents are not working.....oscilating between READY and CONNECTING.

Local agents are working - OK.

I'vet tried different EA's - it is always the same - agents are working localy, but not on LAN.

I searched google and this forum for solution..... found nothing, need your advice.

What might be the cause ?