Illegible (ILL)
The USPS defines this NIXIE code as: The way the address appears on the mailpiece makes it unreadable to postal sorting machines and/or USPS staff. For this, it’s essential to look at the label design and printing, and work to produce a piece that can be accurately read.
The most common factors in determining the source of this NIXE code are:
- Mixed case characters - using a combination of upper and lower cased characters in your address lines, such that some letters may be confused by the postal sorting machines, like "I" (upper cased i) and "l" (lower cased "L")
- Extra leading characters - invalid use of leading zeros which may be interpreted as street numbers
- Misspellings - like "trd" instead of "third" or "3rd"