The newest version of AVAST (see above) downloaded a few days ago, and suddenly all my client apps for Media Mall’s PlayOn could not access the PlayOn server on one of the PC’s which host the server. Another PC with the PlayOn server, but which is not protected by AVAST, continues to operate the PlayOn server normally with full access for all the client apps. I checked the AVAST firewall, and the PlayOn Server is Allowed (see screen shot attachment). Is there any other area of AVAST where I need to whitelist the PlayOn server address?
Although it might be a good idea to restart your device if you have not done so since the last Avast AV update.
Also, temporarily disable the Avast Shields Control via the taskbar to see if this makes any difference.
If it does, enable the shields one by one to determine which one is causing the issue.
Thanks for the quick reply. Unfortunately, I have tried all of your suggestions with no luck. The PlayOn subreddit suggests that there may be an issue with discovery in PlayOn that is being corrected by a yet to be released update, but it did not specifically involve AVAST, so at this point, I am uncertain how to proceed.