Can you keep using it?
Can you keep using it?
Contact customer support if any of these apply
- !The message remains even when the settings and loaded paper clearly match.
- !The printer no longer saves tray or duplex settings correctly.
What to check first
Step-by-step checks
- 1
Consumable check
Check the loaded paper size and the tray setting on the printer.
Start with the official recovery step before moving on to parts or deeper servicing.
- 2
Consumable check
Compare the driver job settings with the paper actually loaded.
- 3
Safe first step
Retry the job once the media size and duplex settings agree.
Background
What this message usually means
Brother shows Size Error DX or Size Error 2-sided when the machine cannot continue a duplex job because the loaded media size or duplex setup does not match what the printer expects. It is usually a media-setting mismatch rather than a mechanical fault.
Diagnosis
Likely causes
The loaded paper size does not match the duplex job.
The tray settings are wrong for the media currently loaded.
The printer is trying to duplex a size or source that is not configured correctly.
Service
When service or replacement is more likely
- -This is a setup mismatch, not a paper jam.
See also
Related codes in this family
Explore more
More Brother printer families
Keep browsing
Where to go next
Source notes
Brother's HL-L5210DN error-message list includes Size Error DX and Size Error 2-sided among the LCD stop messages.
Built around Brother HL-L5210DN-class official error-message guidance. Exact wording can vary by regional firmware and closely related office-laser variants.
Printer error codes can vary a little by firmware, region, and exact model variant. Use this guide as a family-level starting point and stop if the next step would require disassembly or service-mode changes.
Known family variants: HL-L5210DN, HL-L5210DW
Last reviewed: 2026-04-12
Reference: Open reference