The issue is not directly caused by the update. There is no change to the networking in the update.
Something on your computer or your network has changed. It may have changed in response to the update - eg AntiVirus may not recognise the new file as trusted - but the change is occurring in your OS, your software or your network.
Start by answering the questions in post #1 here: https://www.fantasygrounds.com/forum...ions-Explained
If you work thru those questions you will most likely find the fix.
Otherwise post detailed answers to the questions.