Fixed!
Somehow my PC switched to a Public Network. I was digging what possibly could block my PGXL Utility. Went through Windows Defender setting and did not find anything interesting. But when I check my Network center, I found my PC switched to the Public profile. I switched to the Private and PGXL Utility is working now.
I used my radio with PGXL on daily basis and restarted everything before RTTY contest. Everything was working as it should in the beginning of contest. I have no idea how these changes happens, the only thing is questionable what exactly happened during 6600 crash. I have a long list of of the Exeptions on SSDR crash.
Anyway, I happy to find this Network setting and not when switched to a Private Network, everything works fine - PGXL Utility is up and running.
Sergey, KN7K