The Postal Service could not deliver your card and returned it to USCIS. This almost always means the address on file is out of date or incomplete.
What happens next
Update your address with USCIS and contact them to arrange redelivery. The same address problem will affect future notices.
Official USCIS wording
On September 9, 2024, the Post Office returned your new card for Form I-485, Application to Register Permanent Residence or Adjust Status, Receipt Number XXXXXXXXXXXXX, to us. We mailed your card to the address you gave us, but the Post Office could not deliver it. The tracking number assigned is XXXXXXXXXX. You can use your tracking number at www.USPS.com in the Quick Tools Track a Package section. We will destroy your new card if we do not receive an address update by November 30, 2024. Please go to www.uscis.gov/e-request to request that we resend the card to you. If you move, go to www.uscis.gov/addresschange to give us your new mailing address.