Firstly, check the details you’ve entered are correct. Specifically looking for the correct numbers and letters, for example ensuring you’ve not entered a zero instead of the letter “O” (or vice versa!)
For reference, the standard format of a UK vehicle registration number is two letters indicating the area, followed by two numbers indicating the year, followed by three random letters:
AB12 CDE
If the details are definitely correct, and you’re still not able to locate your PCN, it’s possible your ticket has already been cancelled or paid. To check this, you can contact us here.