Your skeleton json file references the following atlas region:
"top": {
"top": {
"name": "Base_m/Base_Top_A",
which is not part of your player.atlas.txt file.
When I change just this single line from
"name": "Base_m/Base_Top_A",
to
"name": "Base_m/Base_Bottom_waist_A",
then it imports successfully.
This looks as if the atlas is not up to date with the skeleton file, you can try re-exporting it.