Sorry unable to map your existing skeleton - frustrated!

[BOOMBOX5C1A]

Hey.  I'm attaching a blend file.  Mixamo will rig the character if the hat is not included.  For some reason, when the hat is included, it gives me the error that it will be "unable to map to existing skeleton".

Can someone take a look at it?

[Ussnorway]

1 the "unable to map to existing skeleton" error means your model is not a standard Fbx... in this case the main issue is the hat tail has two textures on the same part i.e, when you added white stripes to the hat they sit at the same location as the red texture under

the best fix is to bake it into one texture/ material and an image texture is what Mixamo likes best

2 if you repair the hat the error goes away but then you have a new two issues; the model has gaps between the different parts & the overall size/ complexity of the model is far to big for Mixamo

the true size of the model is around a gig with gaps... 30mbs [no gaps] will be workable but 15mb or use different rigging software is better