Mixamo is now taken over by Adobe and with an Adobe ID you can use their services for free currently.

Things to looks at:

What is optimal file size/face count?

The auto-rigger doesn’t have a hard polycount requirement but we recommend staying between 2,000 to 200,000 triangles and 10 individual mesh objects. Try merging small parts to a single object.

Best practice doc here: https://community.mixamo.com/hc/en-us/articles/210310918-Auto-Rigger-Troubleshooting

to try

600k ->

400k ->

100k ->

• recommended is approx 200k FACES

Output format and input to Unity

Ref: https://community.mixamo.com/hc/en-us/categories/200186383

Models not rigging properly straight from Skanect.

To fix: Need to reorientate in Blender and set the origin point to be between the feet.

Move 3D cursor to required origin point

With the model selected right click on current origin point (orange dot)

Move to 3D cursor