Relatively new to minecraft modded servers. Running on Forge 1.12.2, guns do not shoot nor do damage to animals or anything.
I have pvp=true

Are there any other properties I am overlooking?
Mods are techguns, immersive engineering, and journeymap.

Could be the old bukkit compatibility bug where an error is thrown when damaging an entity causing the damage to be avoided.

The versions here should have fixed this already:
https://github.com/pWn3d1337/Techguns2/releases

Server is running and all mods appear to work, except guns do not seem to fire or do damage on npc, or players even when on survival mode and pvp on. I tried also the one from release and no change.

I setup a singleplayer/ open to LAN and everything seems to be working there presumably because everything is handled on the client side. Guns fire, and damage npc, and if players are in survival also take damage.

If there's anything else I can do to figure out the server let me know, debug info, logs, etc.
I'll close issue since this is probably an issue with server setup rather than the mod.

very likely some mod interaction causes an exception. Is there something in the console?. Singleplayer and Multiplayer should not be much different, Minecraft uses server/client structure in SP too.

I'll post later on, but the only mod I started with was techguns alone, and it was the same thing as before. There were some exceptions on the console I figure it was normal.