Consistent 400 (bad request) error when downloading any video.

[WSimpson96]

I am getting the following error when I try to download any video, is there a known fix or is this a known bug?

[bahl33ted]

Same here.

[K80theSHADE]

Workaround: sign out of YouTube via app.
As for age-restricted content? You're ass out.

[lolo83560]

Same problem here, I had a glimpse of hope w/ last comment, it appeared to be back working after logout, but no, end up saying "failed" ... (edit) but after retyring a couple of times it eventually works

Journey :

1. Trying download as always w/o login to YT -> the thing ultimately throws an error "Video unplayable, reason: 'Please sign in'"
2. Shoot ... so logging in
3. Retrying download -> getting the same 400 (Bad request) reported in 1st post
4. Sh*t ... so, logging out
5. retry download -> seems at first working but then soon craps out saying "Video unplayable, reason: 'Please sign in'" ... darn ...
6. Waited for a while (I was typing this comment :) ), then I clicked the retry icon, and then IT WORKED

Seems like you need to give it a couple of retries (while keeping logged out) till eventually it gets through to downloading.