As a federal Retiree, your Required Minimum Distribution is handled by the administrator of the plan.
All employer
sponsored retirement plans follow the RMD rules, including Civil Service
retirement. This requirement is met by paying your annuity periodically. So
your plan automatically meets the requirements for RMDs.
So you can check that all of the distribution represents RMD, and you can move on with your return.See this
answer from TurboTax Margaret:
https://ttlc.intuit.com/replies/5037840