The process of transferring the character I made in Blender to Mixamo

Hello, I am a 3D designer. I designed a character in blender. my character is rigli. but the clothes are not rigi. because when I press ctrl+p and try to rig, I get the error "bone heat weighting: failed to find solution for one or more bones". And when I send it to mixamo I get the error you see below. I want to transfer my character to mixamo. and i want to know what is wrong. thanks.

I will send the blender file to the send message.