Nether Portals Won't Work

Me and my friend we going to enter the nether so we went to 1 of our 2 portals. It didn't work. We tried the portal we build before. Same problem. It wouldn't take us to the nether.
In fact, it did nothing. We tried building a new one and that one didn't work as well.

Edit: In another world the nether works fine so I don't know why this world is bugged

Second Edit: It is not mods. The other world also has mods.