I downloaded a character from Mixano and following the instruction of the official tutorial i tried to retarget the animation blurprint and duplicate it. The proccess completed normaly but the produced animations are not in good shape. The head is angled and partially inside the torso of the character. This happen with every Mixamo character i download (download ready or created with Fuse).
What is the problem?
Did you adjust the pose of your character to match the pose of the source character in retargeting manager?
Yes i did all the example steps.
Try and import the Mixamo character and assign the UE4 skeleton on import. Also export the character in FBX Unreal format, not just FBX.
I think this works (!!!) but the option to export as Unreal FBX is available only for the characters i created using Mixamo (which is perfect) but not for the free mixamo characters and animations. I won’t bother you about this so… Thanks A LOT!
Just wanted to add that this is correct, 
You MUST use the Mixamo character for this to work, and as stated by Unit23, export the character in FBX Unreal format.
I wasted a few hours a month ago trying to use the UE4 mannequin with the website.
I think I had to do just a minor re-targeting in UE4 when I imported the animations to the Mannequin skeleton (spine needed a bit of a stretch if i recall correctly).
I have problems too, so hard… Mixamo dont rig this character ):