The business activity codes have been updated and 454110 is no longer valid. The business activity codes are based on NAICS codes, which were most recently updated in 2022. See page 19 of the instructions to Schedule C for the new list of codes. You can also use the "Lookup my business code" link within TurboTax to search the new codes.
There's no direct replacement for code 454110, you will instead choose a code that more closely relates to your business.