We had a strange occurrence in the last two weeks, so I decided to ask the community in case this is a more widespread problem. We have been using Wowza to stream HLS VoD (HTTP on TCP port 1935) to customers worldwide, and suddenly we started to get an increasing number of reports of "404: playlist.m3u8 not found" (for URLs that were certainly correct) and/or videos stopping after about 1 minute of playback.
We connected through Teamviewer with two different customer's computers to see what might be happening, and opened a live log monitor on Wowza (with tail -f). To our surprise, we saw in both cases a customer starting a video, playing for around 1 minute, and then Wowza received a "stop" signal without the customer doing anything on the player. Subsequent attempts to reload and restart the video failed at the customer side and Wowza did not even receive any requests from their IP address.
We received similar reports from more than 10 customers located in several countries (mostly US and UK, but also Portugal, Norway and Sweden). Meanwhile the majority of customers (including other customers in the countries mentioned before) continued to receive the videos normally, without any problems. We had similar issues with customers in China a couple of years ago, and our solution was to advise them to use a proxy for video playback from our servers, which worked and still works OK.
I could only assume that either the customer's provider was blocking/throttling TCP 1935 port traffic, or some Anti-virus/Anti-malware program on the customer's computer was preventing them from viewing the videos. I checked the user's computer configuration through Teamviewer but I couldn't find anything suspicious. They did have anti-virus programs, but there was no setting that would block video traffic at port 1935.
Seeing all that, we changed the connection port to 443, and all the problems stopped.
Has anyone else noticed similar behavior lately? This only started to occur more frequently the last 2 weeks.