Not sure if this will help chi_johnson since this reply is around two months later, but in my case the problem was that I had a printout of an IP PIN issued by the IRS in October of 2024 that I thought was valid for 2024 taxes. It turns out between October, 2024 and April, 2025 they had issued a new IP PIN for me, without sending any notification. So, once I logged into my IRS account and discovered the new IP PIN they had issued, I was able to update that on my return and it was finally accepted.
Guessing maybe the IRS updates the IP PIN at the start of every calendar year?
Anyway, be sure to check your IP PIN on the IRS website with your login credentials to be 100% sure you are using the most current one. Hope this is useful to someone to save them the 3 hours of frustration I went through earlier today!
