# 0x503 ROUTERERR_DEBUGBOXFULL Debug Mailbox Full

Alarm codes · `0x503` · verification: source checked

The debug mailbox reached its maximum message count.

## Specification

| Property | Value |
|---|---|
| Code | 0x503 |
| Meaning | The debug mailbox has the maximum number of messages. |

## Connected

- Controllers: [Beckhoff TwinCAT 3 Runtime (XAR)](https://machineschema.com/controller/beckhoff-twincat-3.md)

## Sources

1. [ADS Return Codes](https://infosys.beckhoff.com/content/1033/tcadscommon/374277003.html) (accessed 2026-10-26)

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Source page: https://machineschema.com/alarm/ads-0x503  
JSON: https://machineschema.com/alarm/ads-0x503.json  
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite Machine Schema and the original sources.