Exporting a rigged model to Mixamo

Hi, I'm new here and I'm just tryna figuring out how to export my rigged model to mixamo (from maya 2020), for downloading animations. In the beginning I couldn't export the rigged model because it would unbind the joint from the skin, but then I figured out that I needed to delete the bind nodes and I created a new bind pose for the root joint in the script following a tutorial, and then I exported everything in .FBX and re imported it in Maya to see if the rig will still work, and it did, but now when I import the fbx file in Mixamo it says that it is unable to map the existing skeleton. What I can't understand it's if I exported it in a wrong way or if my rig isn't well made so it doesn't work? I don't know, even re importing it in Maya it still works, but in Mixamo it doesn't. Hopefully even with my bad english someone will understand my problem, anyway thank you so much!