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[web player] Always fail playing first 5 songs ("502 Bad Gateway" and multiple "400 Bad Request")


[web player] Always fail playing first 5 songs ("502 Bad Gateway" and multiple "400 Bad Request")






Firefox 84.0.2 (64-bit)

Operating System



My Question or Issue

When I click "play" on a song in a playlist, then it fails to play the song, jumps to the next song 5 times. The 5th song starts to play successfully but stops after 10 seconds.


I can reproduce this problem 100% of the time, regardless of playlist used (tested my own playlists and spotify created playlists) and regardless of song position in the playlist.


I have saved a HAR-file for the whole session where I reproduce this error, but I don't want to upload it publicly as it may contain sensitive information. Reach out to me on my email if you want me to send it over.


However, I've provided some screenshots of the console and network tab of the Firefox developer tools where you can get an overview of what requests fail and what errors/warnings I have.


Looking at other problems people have reported, this problem seems to be something that has occurred on/off for a couple of years. All the other tickets have been marked "fixed" and the most recent one is 5179515.

30 Replies

I've also tested on a Windows 10 Client with Firefox 89 x64, in my case the problem was apparent though...

Yes, I can confirm that behavior. I also have a bunch of POST requests to "" which responds with a JSON payload that contain "message": "License request failed (unknown)". Here's the whole payload for one of those responses:



    "message":"License request failed (unknown)",
    "stack":"\"Te@\\n_handleLicenseResponse@\\npromise callback*_onMessage@\\nr@\\nEventListener.handleEvent*72060/ze</e.prototype._wrapEventTarget/</<@\\nI/</</</<@\\ncreateSessionWithParams/<@\\ncreateSessionWithParams@\\n_requestLicense/<@\\npromise callback*_requestLicense@\\nr@\\n_dispatchFromStore@\\nemit/<@\\na@\\nt@\\n\"",
    "platform":"web_player linux undefined;firefox 84.0;desktop",



I can also confirm that I have the same Widewine version (4.10.1582.2) bundled with my Firefox installation.

Marked as solution

Ive just updated to the latest Firefox stable (89.0) - Disabled the DRM plugin and the setting "Play DRM content", browsed to the spotify web player, the message "You must enable DRM...." appeared, clicked on "Enable DRM" and the newest (4.10.2209.1) DRM plugin was installed and now it works 🙂 

Interestingly, clicking the "Check for updates" in the plugin manager had no effect.

Hi there folks,


Thank you for your replies in this thread.


@axbkbsf76repwsk - it's really nice of you to share what worked for you 🙂


Can the rest of you try the work around that @axbkbsf76repwsk provided? 


We'll be on the lookout for your replies.



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Live, love, laugh and listen to music 🙂

Tried it but the Widewine plugin stays at version 4.10.1585.2 and is not working

attempted this again, also updated Firefox to version 89.0.1. Widevine plugin version still 4.10.1582.2

Hey folks,


Thanks for the info.


In this case we'd suggest you contact the Firefox support. The folks there can look into this further and give you more information about it.


If you need anything else, the Community is here for you.

Ver Moderator
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Multiple people said it did not resolve the problem, but this this was accepted by the moderators as the solution.


But who cares if the problem was actually solved? The important thing is that the KPI's look good!

agreed. i have tried on a fresh installation of both OS and browser, issue persists.


this was said to be a problem with Firefox and not Spotify, and we were even told to contact their support instead. however, using an earlier version of Firefox (from before the issue started) doesn't work. so we can't pin it on Firefox updating and breaking something either. the problem started out of the blue for me anyway, not after a Firefox update.

I had the same problem, but after logging out and then logging in, the problem was solved.

It's so simple that it may not be useful for people who are really having trouble, but I'll share it as a general solution.

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