Upload of 3d model glitches: hovers and moves side to side

[Sontino]

At first when I upload the fbx file to Mixamo it shows the correct model form standing up then a few seconds later the form is all messed up

It swings side to side automatically only the leg is visible and the rest of the body is under the grid

[Ussnorway]

you mean in the Mixamo preview panel yes?

that would be your model and convert it to wavefront Obj then reupload it should fix mate