Windows 7: Firewall blocks javaw.exe automatically and does not show pop-up on update of the bundled JRE

We just tried a multiplayer game with the latest snapshot and it is not working. We cannot connect to the server. I tried hosting on my windows 10 pro laptop and joining from a windows 7 laptop but it could not see any games available on multiplayer. If I try hosting on the windows 7 machine and joining from my windows 10 laptop then I can see the game but it gives a timeout error when trying to join.

We have been using this setup for the resent snapshots and have had no problems with multiplayer. The last game was with 1.13-pre3.

Windows firewall briefly popped up a dialogue about java accessing local networks which I allowed. I have tried manually resetting permissions but it has not worked. I will now try with firewalls disabled.