# How to Fix "Exception in Server Tick Loop"

> This crash means something broke while the server was running a tick. Here's how to find what.

Source: https://www.beaconhosting.org/knowledgebase/json-exception-in-server-tick-loop
Category: Minecraft
Last updated: 2026-10-22

"Exception in server tick loop" is a general crash message: something went wrong during a server tick and the server stopped. The real cause is in the lines below it.

## Find the cause

1. Open **Files** and go to `crash-reports`. Open the newest file.
2. Read the **`Description`** and the first few lines of the stack trace under it.
3. Look for a mod or plugin name, or a familiar error.

## Common causes

| In the crash report | Fix |
|---|---|
| `OutOfMemoryError` | Remove heavy mods, lower view distance, or upgrade your plan |
| `Ticking entity` / `Ticking block entity` | See [How to Fix Ticking Entity Errors](/knowledgebase/how-to-fix-ticking-entity-issues-on-a-minecraft-forge-server) |
| A mod's name in the first lines | Update or remove that mod in **Package Manager** |
| `JsonSyntaxException`, `MalformedJsonException` | A broken `.json` file: often `ops.json`, `whitelist.json`, `usercache.json` or a mod's config. Fix or delete the file named |
| `Failed to check session lock` | See [How to Fix Failed to Check Session Lock](/knowledgebase/failed-to-check-session-lock) |

## A broken JSON file

If the error names a `.json` file:

1. Stop the server.
2. Open the file in **Files**. Look for a missing comma, quote or bracket near the line the error mentions.
3. If it's `usercache.json`, you can simply delete it; the server makes a new one.
4. Start the server.

Can't tell what's wrong? [Open a ticket](/billing/tickets) with the crash report attached.