.jar being deleted leaving .jsons only

when loading some versions it crashes giving me the error: 
Failed to download file.
Name: 1.16.5.jar
URL: https://launcher.mojang.com/v1/objects/37fd3c903861eeff3bc24b71eed48f828b5269c8/client.jar
Error details: Could not resolve host: launcher.mojang.com
Filename on disk: 1.16.5.jar
Path: C:\Users\ameli\AppData\Roaming\.minecraft\versions\1.16.5\1.16.5.jar
Exists: Nonexistent
When I looked through the path \versions\1.16.5 the only file left was the 1.16.5.json.

I have backups of my Minecraft versions thankfully but when I implement the missing .jar file in, the file gets deleted and gives the same error.