What's the url you trying to play? Did you enter https:// in front? Did you read the ingame help?

i'm sorry i can't help more right now but it's late; however as of now i can remember that is was a dropbox URL which should work fine. I tried http, https, messing with the link, nothing worked. Also for an invalid URL, it gave me error 2 instead. I'll be happy to provide more info if needed and i hope i just didn't ♥♥♥♥ up and made a mistake. I'm playing on the 64bits/chromium branch if that can help.

Been having the same issue, a dropbox link i had is considered illegal even though the rest i have work fine. there is no difference I could find that seperated the "illegal" link and the other links

@Flonk: Please paste the link into the comment box. I can't debug it without the link. It could be that the server returned an 403 error or something for that link.

here you go https://www.dropbox.com/s/ft5p4p75lu9zs48/2022-11-28%2022-24-39.mp4?dl=0

This is a video, use mp3 instead.

i remember i used an mp3, although tbh it's been so long i'm not even sure it's still a problem for me
other people in other thread got the same error but i don't even know if it's related, it's been more than 6 months

hm strange, the rest i have are videos and are mp4s which work just fine
https://www.dropbox.com/s/rh0ys1mzjccq1mm/2021-11-08%2014-21-44_Trim.mp4?dl=0
https://www.dropbox.com/s/kc1dvg5gw7had6a/2021-11-06%2012-13-29.mp4?dl=0

Same issues here. Error 20. All I use are mp3 extensions. used a different upload service. Some links work, others don't. Some that worked before now don't, others that did work still do.

Works Fine:
https://steamuserimages-a.akamaihd.net/ugc/2000192155592199672/276B7CEBA28476A4DA36E8BA8FC2C7D64A7B5489/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false


Doesn't Work:
https://steamuserimages-a.akamaihd.net/ugc/2000192155592199172/E0B66364FC1B56F17BC2BA29693397A873372FF9/?imw=5000&imh=5000&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

@UHC Thanks for reporting.

Your URLs are:
https://lfgs.co/u/zuRHV.mp3 (works)
https://lfgs.co/u/gSjSC.mp3 (error)

I reposting them for easier debugging

@flonk: Thanks for the URLs.

I honestly don't know what is causing the error. This error is an GMod engine level error (bass.dll) so far I can tell, so similar addons are affected aswell. There probably is no esay fix possible.

On my end All reported URLs worked. It could be the OS or some installed codics that might help or interfere the game engine on some edge format cases. In those cases the files do not work for everyone or everytime. To avoid such problems, here are some recommendations:
- Use real sound files only.
- Do not use mp4.
- Do not rename mp4 to mp3.
- Do not use Videos.
- Avoid using long files.
- Retry multible times.

I have some extra info I found out. This problem only happens on certain servers. I can use almost any mp3 link on some gmod servers, but for others the same links suddenly don't work.

It might that sv_streamradio_allow_customurls is set to "0" on affected servers and some bug prevent the error being handled differently. Error 20 is likely to be caused by an internally replaced url. There is a distinct error case when you try to playback custom urls on servers with sv_streamradio_allow_customurls 0.

I released an update (rev. 416) related to sv_streamradio_allow_customurls 0 today. It is less likely for error 20 to occur now. Wait until the server has applied the update for them-selves aswell.

News on the error 20 issue:

Some server have their own seperate URL whitelists/blacklists addons independent from this addon. If these addons reject the URL, they might return error 20. This is something this addon can not and will not fix.

If you get error 20 on an otherwise valid URL, please talk to a server admin about this.