Troubleshoot label generation error messages

If you’re seeing an error message while generating a shipping label, here are the most common messages, what they mean, and what you can do to fix it: 

Select Flat Rate box type

Error message: "Error Generating Label: Missing flat rate box selection" or "select flat-rate box type"

If you're using Flat Rate shipping, this error can appear when generating a label in the mobile app. Because the app doesn't support adjusting shipment details, you’ll need to choose a Flat Rate box option on whatnot.com.

To select a Flat Rate box type: 

1. Sign in to whatnot.com 
2. Click on your profile icon 
3. From the Selling tab, open the Shipments page
4. Filter shipments by Needs Label 
5. Find and edit the shipment by clicking the pencil icon 
6. Make sure the Flat Rate toggle is turned on 
7. Select a Flat Rate box type
8. Click save and then try generating the label again

If you're still seeing an error, the website should guide you to select a Flat Rate box type by clicking Add Details.

First-Class Mail Letter issue

Error message: [{"code": "source":"PitneyBowes", "text":"Invalid address provided for toAddress Address"}]

This error happens when trying to ship a First-Class Mail Letter to places outside the continental US, like Hawaii, Guam, or Puerto Rico. It’s a known issue, and we’re working on a fix.

To generate your label, contact Whatnot support. If you’re shipping to Hawaii or a U.S. territory and see this error, we’ll send you a new label, usually within 24 hours and at no extra cost.

Incomplete or invalid address

Error messages:

• "Unable to generate a label: A rate may only be purchased if it was generated…"
• "Failed to generate Shipping Label"

These errors usually mean an address is incomplete or not recognized by the carrier, and usually due to an issue with the buyer’s shipping address.

To fix it:

• Contact Whatnot support to get a corrected label.

• Or, if you recently updated your return address, check it for:

  • Typos or missing info (like apartment numbers, city, ZIP code)

  • Extra punctuation or unsupported characters

  • Then fix it from the Shipments page in Seller Hub and try generating your label again

Customs weight exceeds package weight

Error message: "Total weight of customs items exceeds the total inputted package weight"

For international shipments, your package weight must match—or be slightly more than—the total purchase weight of the items listed for customs. If it’s lower, you’ll see this error message. 

To fix it:

1. Check the weight of each item listed in the shipment (including incremental weight)
2. Add the weights together get the total customs weight
3. Adjust your package weight to match or slightly exceed that total

Example: If you’re shipping ten items listed at 1 oz each, your total weight should be at least 10 oz.

Need more help? 

Contact our support team. We’re happy to help you troubleshoot and get your label generated.