The IP Pin will change each and every year. This is an Identity Protection Pin.
You can get an Identity Protection pin here, or if you lost your IP PIN, you can go here to Retrieve IP PIN.
Here's how you can fix a reject:
Sign in to your account and select the Fix my return button. Follow any “fix it” instructions to update the information causing the rejection.
Note: Not all rejections will have explicit guides to fix the information. You’ll need to navigate to the program area to address the cause of the rejection.
Time-saving Tip: If what you originally entered is correct, you won't be able to e-file. There's probably a data mismatch at the government, a dependent that's already been claimed, or some other situation beyond your control that prevents your return from being e-filed. In this case, your only option would be to print and mail in your return. This article will give you instruction on how to print and mail your return.
reply from CatinaT1 does not apply to DESKTOP app. there is no "Fix my return"
The only place to enter PIN is in "Sign Your 2024 Return" but the "2024 e-filing PIN" field only allows FIVE characters - the PIN from the IRS is SIX characters!
Found the correct answer for desktop users at https://ttlc.intuit.com/community/taxes/discussion/rejected-federal-tax-return-by-irs-code-ind-181-01-ip-pin-is-missing/00/2909067