Fix errors while generating a label

If you’re seeing an error message while generating a shipping label, here are the most common causes and how to fix them.

Flat rate box issue

Error message: "Error Generating Label: Missing flat rate box selection"

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

To fix it:

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 prompt 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:

Option 1: Contact support 

If you're shipping to Hawaii or a U.S. territory and got this error, contact Whatnot Support. Since this is a known issue, we’ll send you a new label—usually within 24 hours and at no cost. This exception applies to this specific issue. For other label changes, please adjust the label yourself. 

Option 2: Adjust the label to change the shipping option 

If you set the weight to 4 oz or more, the shipping method changes right away. First-Class Mail Letter isn’t an option at that weight, so the system will use Ground Advantage or Priority Mail instead.

To edit the weight: 

1. 1. 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 select the order 
      6. Select Edit Shipping Details
      7. Change the weight to 4 oz or more
      8. Save and try generating the label again

You may be charged a fee if you've used your 5 free label adjustments this week.

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 mean an address on the label is missing information or not recognized by the carrier. It usually happens when the buyer’s address is missing infor, but it can also happen if you recently updated your own address.

To troubleshoot: 

• Double check both the shipping and your return address for:
  • Typos or missing information (like apartment numbers, city, ZIP code)
  • Extra punctuation or unsupported characters
• Use the USPS ZIP Code Lookup Tool or your carrier’s address tool to confirm the addresses are valid
• If your return address is incorrect, update it in the Shipments page and try again
• If the buyer’s address looks off, contact Whatnot Support and we’ll help you generate a corrected label

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 listed for each item in the shipment (make sure to include incremental weight too)
2. Add everything up to get the total customs weight
3. Adjust your package weight to match or slightly exceed that total

For example, if you’re shipping ten items that you listed as 1 oz at the time of purchase, your total weight should be at least 10 oz.