Uefy 2.0 (Pro Edition) make Blender's rigify rigs compatible with UE5, also has a FREE version

Hello @Waves I am experiencing the following error:

I have fixed the metarig and added a few new bones following the instructions of the YouTube videos (the vertex groups are currently named as “u_***”), then I press Generate Rig and when I press Build Skeleton is when this error shows up.
Could you please help me? Than you