Why Is My PDF Template Invalid?
3 min readLast updated: February 20, 2026FAQ
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When uploading a PDF template, AutoLetter automatically checks whether the file meets the technical requirements for DHL letter delivery. If validation fails, you will receive an error message. Here you will find the most common causes and how to fix them.
Your PDF must be in the exact DIN A4 format:
Other formats such as US Letter (215.9 x 279.4 mm) or A5 are not accepted. Check in your design software that the page size is set correctly.
All fonts used must be embedded in the PDF. If fonts are only referenced but not embedded, DHL cannot print the letter correctly.
How to fix it:
DHL reserves certain areas on the first page of the letter for sender, recipient, and postage. If your design extends into these zones, the template will be rejected.
The following areas on page 1 must remain clear for DHL. Do not place any of your own content such as logos, text, or images there.
The reserved zones:
| Zone | Purpose | Dimensions |
|---|---|---|
| Sender field | Sender address | 23 x 85 mm |
| Postage field | Postage by DHL | 85 x 16 mm |
| Recipient field | Recipient address | 85 x 21 mm |
AutoLetter automatically inserts the sender and recipient addresses into these areas. Your design must not overlap these zones on the first page.
DHL requires minimum spacing on all page margins:
| Margin | Minimum Spacing |
|---|---|
| Top | 2.3 mm |
| Right | 2.3 mm |
| Bottom | 2.3 mm |
| Left | 12 mm |
Pay special attention to the left margin of 12 mm -- this is larger than the others because DHL needs space there for machine processing.
The maximum file size for PDF templates is 19.5 MB. Larger files will be rejected.
How to reduce the file size:
Use the visual template editor in AutoLetter to create templates directly in the browser. The editor automatically accounts for all DHL requirements -- formats, margins, and reserved zones are handled for you.