Can anyone explain these pkey errors I keep getting?

I am trying to allow a page I created to let users insert a record. I set up a GUI SQL using key value pairs. Now, when it runs, I get the following error " Insert into rp_shipped_2025 failed: you must satisfy the constraint 'Rp shipped 2025 pkey'

This error message has been driving me crazy for quite some time. Nobody seems to be able to explain what it means or how to fix it. I have an id field in the table which is auto-incrementing. At this point I have no idea what else to try.

Now I am also getting a pkey error when trying to import data into a database.

Duplicate key value violates unique constraint "tp_shipped_2025_pkey"

These pkey errors are going to drive me crazy. Is there any way to fix them?

By the way, I have checked the ID field for duplicate values. There are none, plus I am using an auto-incrementing field as the id field.