Uploaded resource packs don't work

I've recently tried to upload a resource pack to my server. Here's the link: https://www.dropbox.com/s/mz6ysxy5jh13wx7/Mctiricity.zip?dl=1

Unfortunately when I entered the world the resource pack did not show up. Instead this error appeared in the log:

[Server thread/WARN]: You specified a resource pack without providing a sha1 hash. Pack will be updated on the client only if you change the name of the pack.

I searched this problem and some of the solutions I found involves editing the server.properties file which I didn't find, and I pretty sure it's unreachable.

Here's the link: https://www.spigotmc.org/threa…packs-not-working.128366/

So I'd like to know how can I add the resource pack in my server.

Thanks in advance.