The song was too soft so i used https://www.mp3louder.com/ to increase the volume of the song. went to the beatmap folder to replace the song and update my map (beatmapsets/1771807#osu/3627372) but theres no sound now. what should i do?
Go to your osu! file and replace the "AudioFilename" with the audio name in the song folder, ex: "Filename".mp3. And be sure to remove any letters that aren't contain in the English Alphabets except symbols.
Rename the audio file to just "audio" the .mp3 is going to automatically applied. The game cannot read your audio file because it is simply looking for "audio".mp3
Osu takes all audiofile names and converts them to "audio" for simplicity sakes, if you add the .mp3 into the filename then it converts it to audio.mp3.mp3 which it does not know how to read.