American Opportunity Tax Credit (AOTC)--why did TT not pick this up?

Just got a letter from IRS.  Says I claimed AOTC for more than 4 years.  Went back and checked and yes, 2024 would make 5.  I have used TTax for the last 20 years.  Why would TTax not know that this was year 5?  Now I need to amend the return and not sure how to remove that credit.  Any advice is appreciated.