Why is YouTube video not playing?

Question

YouTube

I want to share a problem that I had while playing some YouTube videos.
Somewhere between June of this year and to this day, on any device that can be connected to the network at home, in browsers other than Chrome, some videos from the YouTube portal do not play. I noticed the problem when my own video did not start (“An error occurred. Please try again later”). Flash player and browsers are updated regularly, JavaScript is enabled, cookies are removed and the cache is clear. Then I noticed that in addition to my video, some videos of other users also do not play, but something opens without problems.
Regarding the Chrome browser. Here the problematic video starts, but not immediately, but after 50 seconds of waiting. A friend of mine suggested that at this time the required video is being converted for the user to be transferred to him. However, one day at two in the morning Moscow time, I went to YouTube, and all the problematic videos started right away (and so every time).
Contacted the provider. They said that they did not turn on any filters, in general, they did not touch anything. By the way, on its other subnet, even on the old version of the Flash player, everything is played everywhere.
Tried to search the internet for someone with the same problem. It turns out that a similar topic was raised on Habrahabr here . Following the advice, in Linux using the command
sudo tcpdump -q -i eth0
learned the IP addresses of streaming video servers and blocked the range in the firewall. It did not help - the situation repeated itself.
By the way, when I later uploaded another video to YouTube, there were cases when this was repeated for a new video. Then I reloaded it again (it worked for the second or third time).
Give advice on solving this problem.

Answer 1

https://chrome.google.com/webstore/detail/disable-...