The F105 course page 57 shows that you can unlock a financial period. On the Manage Financial Periods GL503000 does not have an option “Unlock” - it only has “Open, Close, Lock, Deactivate”
Please correct manual - but preferably please make changes in Acumatica R1-2020 that indeed a Locked Period can be Unlocked.
Best answer by Jp89
Ok, my error - Must be Financial Supervisor then it works