I have 2 accounts from which I should take my RMD. 1 acc. is all right but I forgot to take it from the 2nd one starting more than 10 years ago. What should I do now?

[KrisD15]

Since the RMD has been neglected for so many years, you might use an Attorney or Tax Professional to handle your case. 

Talk to the administrator of the account as well.

You can file Form 5329 and request at least a partial waiver from the penalty. 

Form 5329 and a statement of your situation should be attached to your tax return.

You still have a couple days to make the withdrawal before April 15th to apply the distribution to 2024 and you should try to do that. You can then add that taxable income for your 2024 tax year return.

The excise tax penalty has recently been reduced from 25% to 10% but I'm not clear if that will be for the late distributions prior to 2023.  

HERE is a link to a similar question.