3704035 - During order confirmation the error message "Posting period & & is locked (check posting date)"

• When confirming activities associated to an order the error message RU428 is prompted "Posting period & & is locked (check posting date)".
• This error can occur during such cost object confirmations like Production Order, Process Order or any other order type which requires activity confirmation. 
• For example in app "Confirm Production Operation" the error can be prompted when attempting to post the confirmations. It is not clear why the error is prompted.

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SAP S/4HANA Cloud Public Edition

Activity Type Confirmation, CO11N, CO15, CO19, COR6N, RU 428, CBTTYPE, Bus. Trans. Type, CO Periods, CO_RU_CHECK_PERIOD_BLOCKED, CO_RU_CONFIRMATION, Time confirming, F3069, F4684  , KBA , CO-PC-OBJ-2CL , Cost Object Controlling (Public Cloud) , CO-PC-OBJ-ORD-2CL , Product Cost by Order (Public Cloud) , PP-SFC-EXE-CON-2CL , Confirmation (Public Cloud) , CO-OM-ACT-E-2CL , Postings (Public Cloud) , Problem