How to resolve connection issues to freedb or Web Sources?
First of all, make sure that Mp3tag has access to the internet. This can often be checked by using Help > Check for new version.... If you're getting a response there, you can be sure that the internet connection works.
If Mp3tag can't connect to the internet, please ensure that the Firewall on your system allows access for Mp3tag. Some routers also have program- or traffic-specific rules.
If you have still problems with accessing online resources, increase the timeout value at Options > Networking to 10 and try again.
How to use a *.src web source file?
Copy or move the *.src file to the configuration folder at
%APPDATA%\Mp3tag\data\sources
You can also just execute the openSourcesDirectory.bat file that automatically opens the correct folder. It either comes with the *.src file or can be downloaded from here.
You can now use the script from the Tag Sources menu or from the 
button.
Please visit the Web Sources category if you are interested in more scripts.
How to find the configuration folder?
Use File → Open configuration folder.
The configuration folder contains the following data:
-
Export configurations
*.mte
%APPDATA%\Mp3tag\export -
Actions
*.mta
%APPDATA%\Mp3tag\data\actions -
Web sources scripts
*.src
%APPDATA%\Mp3tag\data\sources -
Custom genres, column views and tools
*.ini
%APPDATA%\Mp3tag\data -
Library (if enabled)
*.db3
%APPDATA%\Mp3tag\data\library
For a Standard installation, the configuration folder is at %APPDATA%\Mp3tag which usually expands to C:\Users\<username>\AppData\Roaming\Mp3tag.
For a Portable installation, the program directory is used to store the settings.
For a Microsoft Store installation, the configuration folder is at C:\Users\<Your Name>\AppData\Local\Packages\35795FlorianHeidenreich.Mp3tag_rf0p6xgxmspcc\LocalCache\Roaming\Mp3tag\
Discogs is reporting a 401 error: UNAUTHORIZED
In many cases, the problem can be fixed by correcting the system time. This is necessary, because the time is part of the OAuth authorization flow and the signature that is used to communicate with the Discogs API.