v2.7.2 is out.
If the proxy vanished from the tray mid-tagging and Mp3tag showed error 12030, this is the fix. Beatport checks every request again, so the hidden Edge step now runs for everyone. That exposed an old bug: the startup splash was cleaned up from the wrong thread, which takes the whole program down.
v2.7.1, out earlier the same day, makes proxy.log say why if the proxy ever disappears again.
Thanks to @iamyou, whose Event Viewer entry pointed straight at it.
Hi excuse me in advance for any imprecisions, I was trying to use mp3tag(version 3.36.1) as a dj and I kept getting the 403 error, so I found online this proxy that i thought could help me. I downloaded the latest scripts, beatport by stevehero v6.007 and traxsource by jordi and claude v3.0, then proxy v2.7.2, i followed all instructions in the folder but I keep getting that same error, using both beatport and traxsource is there any way you could help me?
EDIT
the program was not able to find the files, I put a direct connect to the folder in the patcher and now it's working fine. Thanks.
Glad you got it working, and thanks for coming back to say how. The proxy looks for the scripts in Mp3tag’s usual folder, %APPDATA%\Mp3tag\data\sources. If yours live somewhere else, a portable Mp3tag for instance, it can’t see them, so Mp3tag keeps going to Beatport directly and gets the 403. Pointing the patcher at the folder, like you did, is exactly the fix.
Out of curiosity, where does your Mp3tag keep them? If it’s a portable Mp3tag, I could teach the proxy to find that folder by itself.
I used a portable setup for this too and with the help of the patcher.exe put it into C:\Users\Owner\OneDrive\Software\Mp3tag\data\tools so it's similarily localised within Mp3tag like a normal installation and always in an expected place and in an appropriate folder separate from Mp3tag's other functionality.
It means maintaining a backup as anything not officially part of Mp3tag's configs isn't saved using File -> Save configuration ... but then again, it is in cloud storage. 
I think %APPDATA% can get iffy with portable versions as tested with $getenv(appdata) as it doesn't point to the actual folder, though $getenv(mp3tagapp) and $getenv(mp3tagappdata) do work. Not sure if the equivalents work with global environments.
Windows Store installations are more problematic but can be solved in Mp3tag using:
$ifgreater($strstr($getenv(mp3tagapp),35795FlorianHeidenreich),0,$getEnv(USERPROFILE)\AppData\Local\Packages\35795FlorianHeidenreich.Mp3tag_rf0p6xgxmspcc\LocalCache\Roaming\Mp3tag,$getenv(mp3tagappdata))
It might also be a shout to let us enter the expected location using the actual proxy.exe to store within the proxy.cfg.
No after downloading them I manually put them in %APPDATA%\Mp3tag\data\sources but the proxy couldn't see them, I don't know why. I could ask my brother to investigate, I'm not a code genius XD
Also do you perchance know a software that could help me with more precise metadata such as mood and energy rating? It would be so userful to not have to do everything manually.
I also wanted to ask if there was a way to tag multiple files once, without having to process each one singularly.
I don't know if this is the right place to ask but thanks anyways.
No need to bother your brother, one detail will tell us. The patcher only asks for a folder when it has already looked in %APPDATA%\Mp3tag\data\sources and found nothing there. So the folder you typed is where your Mp3tag really keeps them. Could you paste that path here? And did you install Mp3tag from the Microsoft Store? The Store version keeps its files in a different, hidden folder.
Tagging several files at once: Mp3tag works per release. Select all the tracks from one release, use a RELEASE search (or RELEASE Direct by URL), and they all get tagged in one go. For singles from different releases there’s no automatic way, it’s one search per track.
Mood and energy: Mixed In Key is the usual one for energy (a 1 to 10 rating) and key. For mood I don’t know anything I could recommend.
@arb thank you for this, all of it went into v2.7.3.
Your layout now works on its own: with the proxy in Mp3tag\data\tools, it walks up from its own folder, finds the portable Mp3tag and its data\sources, no setting needed. And since proxy.cfg and the log sit next to the exe, they live in your OneDrive folder with everything else.
I checked mp3tagapp and mp3tagappdata: I read the environment of a running portable Mp3tag from outside, and they are not in it, so other programs can’t see them (unless Mp3tag passes them to tools it starts itself, which I haven’t tried). That’s why the proxy looks upward from where it sits instead.
The Store folder from your formula is checked too. One thing I didn’t expect: on my PC, which already had the regular Mp3tag, the Store version wrote straight into the standard %APPDATA%\Mp3tag, not the package folder, and File → Open configuration folder did nothing. So in that setup your formula would point at a folder that isn’t there. The proxy checks both.
And your proxy.cfg idea is in as well: tray menu, Scripts folder, Choose a folder… It’s saved as a sources= line, which can also be added by hand.
v2.7.3 is out.
If the proxy was running and Mp3tag still got 403, your scripts were probably somewhere it never looked. Now it finds them in a portable Mp3tag when it sits inside that folder, checks the Store version’s folder too, and if it still finds nothing, says so on the splash and lets you pick the folder yourself.
Thanks to @Imbasto0098 for the report and @arb for the details.
I checked because if i open the patcher I keep getting that message that it can't find the files even though the software now works, and I noticed that it says it's looking in C:\Users\andre\AppData\Roaming\Mp3tag\data\sources; while my files are in C:\Users\andre\Mp3tag\data\sources, I think it considers the folder that I'm using as not the original one but I opened it from mp3tag using the open configuration folder option, the folder in which the patcher is looking doesn't exist anywhere in my files. How can I edit where the software looks for the files like @arb did? Hope this helps.
I downloaded proxy from GitHub.
That helps a lot, thanks. Your Mp3tag keeps everything in C:\Users\andre\Mp3tag, which is how a portable Mp3tag works, so the proxy was looking in the wrong place. Partly thanks to your report, v2.7.3 came out yesterday and handles this. Get it from GitHub, then either:
start it, click the grey “Tagging scripts not found” line on the splash (or in the tray menu: Scripts folder, Choose a folder…) and pick C:\Users\andre\Mp3tag\data\sources. It remembers that folder from then on.
or do what arb did: put mp3tag_proxy.exe in C:\Users\andre\Mp3tag\data\tools (create the tools folder), and it finds the scripts by itself.
Once it knows the folder, it checks your scripts at every start, and if anything needs fixing you get a Fix tagging scripts… item in the tray. So you don’t need the separate patcher any more and can ignore its message.
v2.7.4 is out.
Traxsource searches with an & in them, like "Drum & Bass", reached the site cut off at the &. Fixed, and that one had been there since the very first version.
Also, if you open other sites through the proxy in a browser, their pages now load properly. That's a side door rather than what the proxy is for, but there's a note on it in the README.
Thanks to @yorickausyps, whose report led to both.
v2.8.0 is out.
Beatport took the track list off its release pages, so Release Search and Release Direct showed recommended releases instead of the tracks. The proxy now puts the tracks back from their own pages. A release takes a few seconds longer, and you don't need to change anything in your scripts.
Bandcamp can be searched by artist and album name again, with release dates. It needs the proxy running and the Bandcamp source 0.5.0: [WS] Bandcamp (search by URL) - #81 by The_Zhu
The tray menu now shows at a glance what's going on: the version, when the last request came in, today's counts and whether your scripts are OK.
Thanks to @Norbox for the quick report and @yorickausyps for bringing up Bandcamp.
v2.8.1 is out.
Bandcamp Search now shows cover thumbnails in the results list. Thanks to @yorickausyps for spotting it.
v2.8.2 is out.
If your first Beatport search after starting the proxy failed with error 12002 and the second one worked, that's fixed. Thanks to @Norbox for the log that showed it.
v2.8.3 is out.
If Bandcamp Search lists results but opening one gives 403 on your PC, add a line bandcamp_pages=1 to proxy.cfg and restart the proxy, the README has the details.
@Norbox your log shows 2.8.2 doing its job: the Cloudflare check took 14 seconds, the proxy asked Mp3tag to wait twice, and the results came through at 16. Thanks for the tomatoes 
v2.8.4 is out.
With bandcamp_pages=1, Bandcamp covers now come through the proxy too.
