Crash and Lag Diagnosis

When your server crashes or runs slowly, diagnosis reads what happened and explains the likely cause. It looks at the console output, the crash report and the server's recent stats, then proposes a cause with a confidence level and, where it's safe, one or more fixes you can apply with a click.

What Diagnosis Does

For each diagnosis, Plex Host:

• Reads the last 500 lines of console output
• Reads the crash report, if the game wrote one
• Reads the server's recent stats, such as memory use
• Proposes a likely cause, with a confidence percentage
• Lists the evidence it used, quoted from those sources
• Offers fixes you can apply, and steps for anything you have to do yourself

A diagnosis is a suggestion. Nothing changes on your server until you choose to apply a fix.

Where to Find Diagnosis

After a Crash

When the server crashes, a banner appears at the top of the Console page showing when it crashed and the exit code. From the banner you can:

• Diagnose: start a diagnosis of the crash
• View diagnosis: open a diagnosis that is already finished. The banner shows Diagnosis ready when it is

If automatic restart is paused after repeated crashes, the banner says so.

When the Server Is Slow

On the Console page, select Why is it slow? to diagnose lag. It reads the live server, so the server must be online. When it is offline, the button is unavailable and tells you to start the server first.

Diagnose now reads the newest crash, or the live server when there is no crash to read.

Crash History

The Crash history card lists recent crashes with their time, exit code and whether the server ran out of memory. Open a crash to see the console output from that moment, and to open its diagnosis if one exists.

Health Card

The Health card on the Overview page shows your last crash, your last diagnosis and your uptime for the month. Select the uptime to see the outages behind it.

Automatic Diagnosis After a Crash

You can have diagnosis run on its own after every crash:

1. Go to your server and open Settings
2. Open the General section
3. Turn on Diagnose crashes automatically

When the diagnosis is ready, you receive a notification titled Diagnosis ready.

Reading a Diagnosis

Open a diagnosis from the crash banner, the crash history or the Health card. It shows, from top to bottom:

• Summary: a plain-language description of what happened
• Cause: a chip naming the likely cause, such as Out of memory, Mod conflict or Port already in use, with its confidence level
• Evidence: the lines from the console, crash report or stats that support the cause, labeled by source
• Fixes: each proposed fix, with its risk level: Low risk, Medium risk or High risk
• Do it yourself: steps for anything Plex Host can't change for you, such as updating your plan

If some proposals were removed by our safety checks, the Fixes section says how many.

Outcome

After a fix is applied and the server stays online for ten minutes, the fix shows one of these outcomes:

• Resolved: the server stayed online for 10 minutes
• Came back: the server crashed again after the fix
• Unknown: we couldn't tell whether the fix held

Applying a Fix

To apply a fix, select Apply on its card. Plex Host makes the change. Some fixes also restart the server.

• Fixes marked Takes a backup first create a backup before they change anything. If the backup fails, nothing is changed.
• While a fix is being applied, the card shows Applying…. The check that the server stays up runs ten minutes after the change.
• A diagnosis holds one applied fix at a time. To try a different fix, wait for the current one to finish.

Permissions

Each fix needs a permission on the server, the same ones used elsewhere in the dashboard:

If you don't have the permission, the fix shows an error and nothing changes. See permission levels.

Limits

• Monthly diagnoses: each plan includes a number of diagnoses per month. When you use them all, you can't start new ones until the next month.
• Daily limit: a single server can only run a set number of diagnoses per day.
• Availability: Plex Host can temporarily turn diagnosis off for the whole platform. When it is off, you'll see a message asking you to try again later.
• Log window: only the last 500 lines of console output are read. Older output is not included.

Troubleshooting

• "There's no crash to diagnose yet": the server hasn't crashed. Use Why is it slow? or Diagnose now on a running server instead.
• "We couldn't read this diagnosis": reload the page. If it still fails, select Diagnose again for a fresh diagnosis.
• "Couldn't diagnose": something went wrong while reading the logs. Try again in a minute.
• No safe fix to offer: the evidence did not point to a fix Plex Host can apply safely. Start with the evidence and the Do it yourself steps.
• "The restart failed": the fix was applied, but the server didn't restart. Restart the server yourself.
• "Another fix is still being applied": wait for the current fix to finish, then try again.
• "The backup before the change failed": nothing was changed. Check your backups, then apply the fix again.
• Outcome shows "Came back": the fix did not stop the crash. Run a new diagnosis to get an updated set of fixes.