no ops.txt only ops.txt.converted same for banned-payers ans whitelist on server

What I expected to happen was...:
I was trying to put a player in ops.txt file at first manually( I then tried using a command but same result) so I expected to have this palyer as ops when the server was put online

What actually happened was...:
when the server was turned on it transformed the ops.txt file into ops.txt.converted file and the ops wasn't working

Steps to Reproduce:
1. manually or through a command put ops in ops.txt file
2. turn on server