Direct Mail

USPS Returned Mail Codes

By 1 April 2024April 29th, 2024No Comments
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USPS Returned Mail Codes: Most Common Mail Return Codes and Their Solutions

Did you ever receive mail returns with giant, yellow stickers on them? These stickers or labels carry the USPS returned mail codes, and deciphering what they mean can be confusing.

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A recent USPS audit found 40,000 undelivered mail items across two post offices in Columbus, Ohio. It isn’t surprising that the Post Office cannot deliver every package or envelope successfully. Simply because it stores some items for redelivery and returns others to the sender with USPS return mail codes that tell you why.

So how can you decrypt these codes and resolve the problem?

And how to avoid getting mail returns in the first place?

Keep reading further to find the answers and improve your logistics system!

What Are USPS Returned Mail Codes?

You may know the USPS return-to-sender codes by several names, like Nixie or Undeliverable-As-Addressed (UAA) codes. USPS mentions them on the yellow Nixie labels attached to the items before redirecting mail back to the sender. 

Earlier, it was hard to deal with UAA mailpieces because the mailers were clueless about why the Post Office did not deliver their packages. However, now, the Nixie codes help inform the sender of the problem, allowing them to move ahead.  

To combat mail returns, senders often use NCOALink and CASS from USPS. These resources enable them to spot the issues beforehand and not wait to get the USPS return mail codes to resolve the problem. 

The benefit? Businesses can save thousands of dollars in postage yearly and cut wastage by mailing items to deliverable addresses. 

This quote by Dave Ramsey perfectly fits this context: You must gain control over your money, or the lack of it will forever control you. Companies must take measures to save on resources, postage, etc., to increase their revenue visibly and boost efficiency. 

Meanings of Commonly-Used USPS Returned Mail Codes

We have listed below a series of USPS returned mail reason codes to help you understand them better. Thus, you can be aware of the issues and take the necessary steps to avoid them the next time you send a mailpiece. 

Not Deliverable as Addressed – Unable to Forwarding

It is one of the most recurring USPS return mail codes senders get and means that the carrier cannot deliver the item to the address on the label. The primary reason is that the addressee has shifted to a different location, but:

  • There is no mail forwarding address,
  • The addressee has not filed a change-of-address (COA) request yet, so USPS does not know their new address,
  • The forwarding request is no longer functional,
  • The sender or addressee failed to pay for the forwarding postage,
  • Or the sender endorsed the item with the words ‘DO NOT FORWARD.’ 

Solution: Run your addresses through NCOA software like PostGrid before shipping to send items to correct, updated addresses. 

Insufficient Address

This UAA code is also among the most commonly-seen USPS return-to-sender codes and means that:

  • Some essential part of the delivery address is missing, like the city, route number, state, street address, ZIP code, etc. 
  • A missing PO box, suite, or floor number restricted the carrier from finding the intended destination. 

Solution: If you see such USPS returned mail codes, add the missing details and reship the item. 

Returned for Better Address

The ‘Returned for Better Address’ Nixie code is similar to ‘Insufficient Address’ It means the package or envelope information isn’t enough for delivery. 

Solution: Modify the address a bit to offer more details to the carrier, or use PostGrid’s direct mailing and address verification solutions to do everything automatedly. 

No Such Number

You may also get USPS returned mail codes saying USPS didn’t find the apartment or house number you wrote on the item. For instance, if you write 52 Olive Street but there are only houses 11 to 45 in that area. In such scenarios, the Post Office may need to send back your parcels unless they run a name search and find the correct address in their system. 

Solution: Always check the numbers in your addresses for errors, swaps, extra zeroes, etc., to avoid getting such USPS return mail codes for such minor mistakes. 

Returned For Postage

Imagine you forgot to affix the correct number of stamps covering your postage costs. The Post Office does not process such items from the start and returns them to let you apply the postage and reship the same. Unlike other USPS returned mail reason codes, you only have to pay the postage on time in this situation. 

Solution: Calculate the correct postage using the USPS postage calculator and attach the correct postal fees before you drop off your items in a mailbox. 

Attempted – Not Known

This code says that USPS attempted the delivery but could not deliver because the addressee does not live at the address. It is one of the most complicated USPS return-to-sender codes to decrypt. NCOA or CASS does not guarantee whether a person resides at a specific address if they didn’t file an address change request. 

Solution: Combine data from multiple resources to confirm your intended recipient’s address and avoid such USPS return mail codes on your items. If you want to avoid the legwork, use PostGrid’s direct mail API for mailing instead. 

No Mail Receptacle

Have you seen people living in gated houses with their mailboxes near the door instead of the gate? Also, some customers living in gated communities have a joint mailbox. 

The USPS returned mail codes that say ‘No Mail Receptacle’ mean that the carrier cannot deliver the item to the recipient’s mailbox because of the abovementioned reasons!

Solution: Mention the joint mailbox number or address instead of a recipient’s address. 


Some USPS return mail codes are easily avoidable, like this one. It says that the address is illegible or impossible to read. You may face this problem only if your staff writes every address manually using a pencil or pen. Writing addresses instead of printing may also cause issues because of weather conditions. For instance, your package can get damp, and the ink might blot. 

Solution: Print and stick address labels to your mailpieces and cover them with clear tape. 

Moved, Left No Address

Seeing these USPS return to sender codes is not uncommon because 9.8% of Americans move yearly. Many people change their residence or office address but fail to report them to USPS. Thus, the Post Office has no records of their addresses leading to mail returns. 

Solution: Use an NCOA-processing, CASS-certified mailing vendor to check the details before mailing to avoid getting these USPS return mail codes on your parcels. 

Temporarily Away

Sometimes, your recipient is unavailable at their homes for a short span. Perhaps, they went away for a vacation or because of other reasons. Most people avail of the mail forwarding service at such times, letting USPS deliver their mail temporarily to the new address. But, if not, the Post Office returns the item to you with USPS returned mail reason codes so you can ship again after a few days or weeks. 

Solution: Confirm the recipient’s availability beforehand and suggest they use the Informed Delivery postal feature to stay updated regarding incoming mail. 


The recipient does not live at the mentioned address any longer, and the apartment or house is vacant. 

These USPS return mail codes are simple and upfront to understand. And a DPV address check can help you spot all vacant addresses effortlessly. 

Solution: To avoid receiving mailpieces with vacant USPS returned mail reason codes, print, and mail using online solutions like PostGrid. 

Outside Deliverability Limits

Some rural places or areas with adverse weather conditions are non-serviceable by USPS. If you ship items to such addresses, the Post Office endorses them with USPS returned mail codes and returns the mailpieces to you. 

Solution: Check if you mistakenly mentioned an incorrect city or street name. If not, use a different carrier or try finding a PO box number to mail to such recipients. 


The addressee didn’t accept the item or refused to pay for the postage due. 

Solution: You cannot avoid such USPS returned mail codes, primarily for those customers who order COD items. For shipping marketing items, try filtering out recipients who don’t wish to receive mail from you. 

Box Closed – No Order

If you ship to a PO box address and get such USPS return-to-sender codes, it means that:

  • The PO box is no longer working because of the non-payment of fees. 
  • The recipient stopped using the PO box, and there is no forwarding address. 

Solution: Update your lists from time to time to get the new addresses of your customers and prospects. 


The USPS returned mail codes that say ‘Deceased’ are pretty straightforward. Unless you address an item to the ‘Occupant,’ the carrier sends it back. 

Solution: Use CASS records to remove entries of deceased customers or update the addresses with someone else’s name (like a family member). 

No Such Street and No Such Office in State

These two USPS returned mail reason codes mean you mentioned a street or Post Office name that is non-existent.

Solution: Cross-check your street addresses, primarily if they are similar to other street names. 

Returned to Sender Due to Addressee’s Violation

There can be several reasons for getting these USPS return mail codes, but most involve false representation by the addressee. 

Solution: You must not reship items to these addresses because you may get them back again. Instead, remove these entries from your mailing lists to prevent these USPS returned mail codes and save on postage. 


Items with the ‘Unclaimed’ USPS return to sender codes could suggest that the recipient does not want the mailpiece or is unaware of its receipt. If the recipient does not take out their received mailpieces for a long time, a carrier might take them back to the Post Office. 

Solution: Use an address checker to see if you sent the item to the correct recipients. 

How Can PostGrid’s Direct Mail Solutions Help You Avoid Getting USPS Returned Mail Codes?

PostGrid’s automated direct mail services assist you during every stage of your printing and shipping cycle. It allows you to prepare and produce on-demand and bulk mailing items according to your preferences. So, no more purchasing paper stock, packaging items, ink cartridges, stamps, labels, etc. Nor do you need to look for a printer to print your orders!

Also, PostGrid allows you to ditch USPS return mail codes by noticeably reducing the number of returns! Our solutions ensure you avail of a 99.99% deliverability ratio by verifying your addresses before mailing

Currently, we offer two pricing plans to our clients with varying needs, and they are:

  • Starter: You can use our Starter membership for free and only pay the per-piece prices for the item you mail. Thus, you have more flexibility to ship up to 500 mailings every month without committing to anything. 

You get mail tracking, access to our standard print delivery network, and up to ten design templates with this plan. Additionally, you can quit seeing the USPS returned mail codes by validating your addresses before shipping.

  • Enterprise: The Enterprise membership offers many more features, like HIPAA compliance, native integrations, unlimited templates, etc. Also, you can verify innumerable addresses before mailing to avoid the USPS return mail codes using this plan. 

Talk to sales now to discuss your requirements and get the best quote.


Getting mail returns with USPS return-to-sender codes or yellow Nixie labels can be distressing. They tell you something is wrong, and you need to pay again to reship the items correctly. It means—a loss of time, money, resources, manual effort, and brand reputation.

PostGrid’s direct mail API can allow you to prevent these problems and ship effectively. Everything is online and automated, so you only need to push a few buttons on your device, and voila!

Click here to learn more about how we help clients not get USPS returned mail codes and ship accurately.

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