https

I was facing the same problem, I have fixed this on github and submitted pull request to the original developer, Let’s see if he adds it to the plugin code.

You can check out the fix if you want –

https://github.com/Nikschavan/wp-gfycat/commit/0170506e125b44c6fb2d9e387a4ca7298266d55c

Download zip –
https://github.com/Nikschavan/wp-gfycat/tree/strip_protocol