How to troubleshoot shipping label printing problems

Are your shipping labels failing to print, feeding extra blank labels or printing across two labels? Here are the checks to help you narrow down the issue.

If your ZPL printer is disconnected or not detected, follow How to print your Shipping Labels in ZPL for QZ Tray setup and reconnection checks.

Summary:

1. Printing errors and PDF downloads
2. Check the source ZPL
3. Extra blank labels or labels split across media
4. Faint Poste Delivery Business labels
5. Poste Delivery Business label orientation
6. Label cut off: is the PDF itself incomplete?

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1. Printing errors and PDF downloads

Why does label printing fail when printing many orders at once?

If a PDF does not open or download when printing a large batch of labels, reduce the number of orders in the selection and try again. In one documented case, printing worked with 50 orders or fewer, while 51 or more triggered a success message but did not open the PDF or download a file. Refreshing the page with F5 and re-running the print can also help.

What should you try first?

1. Refresh the page with F5.
2. Print a smaller batch of labels.
3. If needed, split the job into blocks of 50 or fewer orders.
4. Check whether the PDF opens in a new tab or is blocked by the browser.

What if the top Print button shows an error?

If the top Print button returns an FPDF error: Error while decompressing stream, use the document icon next to the sand timer to open the label instead, then print it from there. This file path can still work even when the top Print action fails.

What if label printing returns an unauthorized carrier error?

If printing labels returns a carrier error such as Unauthorized or an expired access message, the issue is returned by the carrier connection. Review and follow the carrier-side procedure for reconnecting or refreshing access, then try printing again.

Which browser checks are worth trying?

If the error happens from the top Print button:

• Try an incognito/private window
• Try a different browser
• If the same behavior appears across browsers, use the document-icon workaround to print the label

Summary

For shipping label printing problems, the most practical checks are to reduce batch size, refresh the page, try the document-icon path for printing, and verify carrier connectivity when the error is returned by the carrier.

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2. Check the source ZPL

Start by comparing the generated label with what comes out of your printer.

1. Open the Labelary ZPL viewer.
2. Preview the source ZPL for the affected label.
3. Check whether the preview shows the complete label and any extra blank pages.

• If the preview is correct and has no blank pages: an extra blank label during printing points toward printer configuration. Continue with the media and alignment checks below.
• If the preview also shows a problem: do not assume that printer configuration alone is responsible.
• If the problem is faint printing or orientation: see the relevant Poste Delivery Business section below.

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3. Extra blank labels or labels split across media

Does the printer feed a blank label after each shipping label? Or does the printed content start too low and continue onto a second label? Check the physical media and printer configuration.

These symptoms can be consistent with calibration, alignment or print-dimension issues, but a photo alone does not establish the cause.

1. Check the actual width and height of the physical labels loaded in your printer.
2. Match the printer's configured label dimensions to those measurements rather than assuming a 10 × 15 cm format.
3. Check the margins for content extending beyond the available space.
4. Check the printing orientation.
5. Check any vertical offset, especially if printing starts too low.
6. Check the media type. For labels separated by gaps, use gap media rather than continuous media.
7. Calibrate the media sensor following the procedure for your specific printer model.
8. Apply the settings.
9. Restart the printer.
10. Test printing a single shipping label.

If blank labels or splitting continue, ask a specialized printer technician or your system administrator to inspect the printer configuration.

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4. Faint Poste Delivery Business labels

Code received from Poste can contain an SD command that sets print temperature to 15. This means faint printing is not necessarily controlled only by your printer preferences.

Our Support Team can assess whether to enable an account setting that removes this printer-setting code received from Poste. This is not a self-service setting. After it is enabled, use the temperature appropriate for your printer.

For the carrier connection settings, see How to connect Poste Delivery Business.

To have this setting assessed, write to our Support Team and explain that your Poste Delivery Business ZPL labels print faintly.

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5. Poste Delivery Business label orientation

ShippyPro cannot change the orientation of labels received from Poste Delivery Business.

• You can check whether another carrier-supported label format available in the connection suits your workflow. See the Poste Delivery Business connection guide for the connection settings.
• You can also check the printer's orientation settings with your technician or administrator.

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6. Label cut off: is the PDF itself incomplete?

Is part of your label or a barcode missing? First check whether the PDF itself is incomplete or whether the content is cut off only on the thermal print. Here's how to separate the two situations.

1. Open the affected PDF before printing.
2. Check whether all the label content, including the bottom and any second barcode, is visible.
3. Compare the PDF with the printed label.

If the PDF itself is incomplete: PostNord ZPL-to-PDF conversion

If your PostNord carrier connection uses ZPL and your Ship API request asks for PDF, test these parameters in your Ship request:

"LabelType": "PDF", "LabelWidth": 10, "LabelHeight": 20

These parameters restored the missing second barcode in a tested PostNord PDF. Support also obtained a complete PostNord PDF with "LabelWidth": 10 and "LabelHeight": 19, keeping "LabelType": "PDF".

For connection details, see How to connect PostNord to ShippyPro.

Before sharing dimensions across other active carriers, test their resulting labels against your current print settings. You can submit Ship test calls through Test Request in the Ship API documentation using your ShippyPro API key.

If the PDF is complete but the thermal print is cropped

If all the content is visible in the PDF but part is missing on paper, try these browser checks:

1. Clear your browser's cache and cookies from its history section.
2. Update your browser.
3. Try another browser.
4. Test printing in an incognito or private window.

If the problem persists, a possible next step is to reinstall your printer using the guide for your operating system: Windows setup guide or Mac setup guide.