Do you mean tax on excess "contributions"? If so, it sounds like you may have inadvertently indicated that you contributed to a retirement account. I suggest you review your deductions section to if that is the case. If it is not, please provide some additional information to help us identify where the problem is coming from.
I copied the name of the tax literally from Turbo Tax. It said 'excess accumulations', not ;contributions'
Did you take all your RMD? Did you take it out of more than 1 account?
Turbo Tax changed this year. When it asks about the RMD it is only asking for that one 1099R you are entering. On each 1099R you need to say Yes it was the RMD and only enter the amount from box 1 on that single 1099R for the RMD, not the total RMD for all and even if it is more or less than the total.
Until they fix it try Expert DavidD66 excellent answer here,
https://ttlc.intuit.com/community/retirement/discussion/re-rmd-mismatch/01/3488686#M234445