ffmpeg add audio to video not working in below command in below command final video is created but sound of second video is muted after some time.
here duration of audio and video is same.

ffmpeg -y -i intro.mp4 -i videoaction.mp4 -i outro.mp4 -i audio1.mp3 -i vcs-watermark-video.png -filter_complex "[0:v]drawtext=fontfile=FutuMd.ttf: text=helloworld: x=300: y=450: fontsize=40: fontcolor=white: enable='between(t,2,5)',fade=t=out:st=5:d=1,setpts=PTS-STARTPTS[v0]; \
[1:v][4]overlay=W-w-5:H-h-5,fade=t=in:st=0:d=1,fade=t=out:st=63:d=1,setpts=PTS-STARTPTS[v1]; \
[2:v]fade=t=in:st=0:d=1,setpts=PTS-STARTPTS[v2]; \
[3:a]volume=enable='between(t,36,44)':volume=-10dB[3a];[1:a][3a]amix=inputs=2:duration=shortest[maina]; \
[v0][0][v1][maina][v2][2]concat=n=3:v=1:a=1[outv][outa]" -vcodec libx264 -c:a aac -ac 2 -map "[outv]" -map "[outa]" finalvideo.mp4
The audio.mp3 is likely shorter. Set duration=first in amix.