Unexpected response while upload chunk

i had everything working with companion, uploading etc
i added a post-finish file script to change the filename back to the org and now when i go back to upload from say dropbox i get this error

i renamed my post-finish script so it doesn’t get envoked and still got the same error

my companion uploads url is set to my tusd uploads url
it gets to 50% uploads and then fails

any ideas would be much appreciated