[MODDED] An Item with the same key has already been added. Key: c20d5e00d77ae0fcbf07e1f4

You've not got many options;

1) Find and cleanly remove the item with the key from your profile JSON found in `user/profiles`

2) Delete the profile and start again

Just saw your reply, looks like you've attempted to remove the item and have not done it correctly. Try running your JSON through a site like: https://jsonlint.com/

It may help you find what's wrong.