Hi Noris,
The issue was actually caused by AVG. I was able to duplicate and solve this problem as per this thread: Roon blocked by AVG, please help.
The problem is that as you disable AVG the roon works but when you re enable AVG sometimes it keeps working sometimes it doesn’t. However when I changed the settings in AVG as per that post it consistently works now My apology to Windows. Got your private message.
Thanks,
Jakub