Optifine_fabric

I dont know why but I can't add a resource pack to my server (The option is grey as shown below) I cant drag anything into it, can someone help?

hi! So I was trying to join my friends server, and on the server page it says Which means it is a server on minehut, but when i try to /join okayyessirrr it says "could not find the server" How do i fix this?