How to Fix an All the Mons (ATMons) Server That Keeps Crashing
All the Mons (ATMons) crosses the ATM10-style tech tree with Cobblemon's Pokemon-catching layer, including Legendary Monument structures. Most server crashes trace to one install mistake rather than a mod bug — but two specific, documented bugs are worth knowing by name if you've ruled that out.
See the All the Mons pack page for sizing before you chase anything else.
1. Installed the client pack instead of the server files
By far the most common reason an ATMons server won't boot at all: the CurseForge client download bundles client-only mods (shaders, HUD, resource packs) that have no server-side implementation and throw a hard crash the moment a dedicated server tries to load them.
Fix: on the pack's CurseForge page, download the dedicated "Server Files" / "Server Pack" release specifically — it's a separate download from the regular install button, built with client-only mods already stripped.
2. Legendary Monuments crashing against the Nature's Aura altar
A documented bug: Legendary Monuments' Ingredient mixin fired incorrectly when interacting with a Nature's Aura altar, crashing the server. The ATM team fixed this upstream in ATMons 1.2.0.
If you're seeing this specific crash, check your pack version first — updating to 1.2.0 or later resolves it without any server-side workaround needed.
3. Mekanism fission reactor lagging the server into a mass disconnect
A reported pattern: starting a Mekanism fission reactor causes the server to lag progressively over 2-60 minutes, then disconnect every player at once. This reads like a crash but is actually a severe tick-time degradation — the reactor's simulation load builds up rather than failing instantly.
If a player just started a fission reactor before the lag began, that's the first thing to check — pause or remove the reactor and see whether tick time recovers before assuming it's something else.
4. The underlying ATM10 tech-tree crash classes
Past the three causes above, ATMons inherits the same Refined Storage overflow, tick-timeout and RAM-pressure issues as base ATM10 — see our ATM10-family coverage for the full breakdown if a crash doesn't match any of the Cobblemon-specific causes here.
FAQ
My ATMons server won't even reach the main menu / loading screen — why?+
The most common cause by far: installing the CLIENT pack instead of the dedicated SERVER files. The client bundle includes client-only mods a headless server can't load, and CurseForge's app doesn't warn you that you've picked the wrong download. Always grab the pack's "Server Pack" / "Server Files" link, never the regular install button.
Is All the Mons actually just ATM10 with Pokemon mods?+
Functionally close — ATMons layers the Cobblemon mod and Pokemon-themed structures (including Legendary Monuments) on top of an ATM10-style base, so it inherits ATM10's tech-tree crash classes on top of its own Cobblemon-specific ones.
Was the Legendary Monuments crash ever actually fixed?+
Yes — the ATM team's own changelog lists it fixed in ATMons 1.2.0: Legendary Monuments' Ingredient mixin was firing incorrectly against the Nature's Aura altar. If you're still seeing it, you're likely on an older pack version and should update.
Host All the Mons from the actual server files
CoalHost installs ATMons from the pack's dedicated server release, not the client download, and runs the auto-fix pipeline that catches client-only mods before they reach boot.
View Cobblemon Hosting →