YouTube 403 error #94

JohnBlackburne opened this Issue Nov 16, 2014 · 7 comments


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This is an odd one. One and one only youTube video isn't working for me - I get a 403 error on the video asset - until I load Flash. It's this one

It's notable for having a song title longer than almost any other. See

That should not make much difference though, as it uses the YouTube heading which is normally much longer than any song title. As it's only one video and I can watch (and have watched) it using Flash this has to be very low priority.

hoyois commented Nov 22, 2014

Thanks for the report. This must be a stupid bug in YouTube's URL query parser. It doesn't like something in the title string which is appended at the end of the URL; not sure what exactly that is yet.

hoyois commented Dec 3, 2014

Did YouTube just fix this?


Not for me - still doesn't load and I get a 'The requested URL was not found on this server' if I try to download via the menu. And I'm bang up to date according to the App Store ah a Safari update. Be right back. No, still not working with Safari 8.0.1.

hoyois commented Dec 4, 2014

In-browser playback works consistently for me now. Download still doesn't work but the error in the Downloads popup is "Cannot open file", which I've never seen before.

Before I had determined that the issue has to do with the length of the 'title' query parameter, although how YouTube actually computes the length is not clear. Unfortunately this is a nightmare to investigate because when you get it to work once it then always works for some time, perhaps because of some caching on YouTube's server.

bo3rnd commented Dec 4, 2014

I noticed that there is not always a 403 error with the video which is linked in the first post.
It seems it depends on the server which is serving the video, some of youtube's servers are giving an error and sometimes the download works, but the title parameter is ignored and the file is just named videoplayback.mp4


Sorry yes, the 403 error in the log is something to do with Google+ being blocked which also occurs on other pages. This is a 'file not found' problem which doesn't put an error in the log but fails whichever way you try to access it.

hoyois commented Dec 7, 2014

Luckily it stopped working again today and I was able to investigate. The "file not found" error happens precisely when the 'title' parameter has unescaped length greater than 228 (each Japanese character counts as 3). I will fix this in the next update.

The "Cannot open file" error I mentioned earlier had nothing to do with YouTube and is literally because HFS+ cannot create a file with filename longer than 255...

@hoyois hoyois closed this Dec 7, 2014
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