Why do I have a $126 Penalty/Interest on my 2023 Tax return? How do I find out what that fee is to prevent in future and possibly reverse the charge?

I owed Fed over $4000 dollars in taxes and refund on State tax of less than $1000. 2022 also I owed around this much to Fed and I paid in full amount both years. Don't know where the penalty is coming from. It is showing on Line 38. 
Thanks for any reply.