If you go to account -- query for 1980 - click on the demands tab -- how are they setup?  

In posting controls -- PP1 -- do you just have account setup?  

Hi, Search for 1980 in “Account” and check the Requirement, whether any other Code part is made Mandatory or Blocked.

If it is Mandatory and the Transaction doesnt Capture the Code part (or you have not set up posting Control to Capture the Code part) then this Error will trigger.

If it is Blocked and the transaction is Capturing the Code Part then the Error will be Triggered.

The Easiest way to come out of this is to make that particuler Code part Requirement to “Allow” (use the Drop Down Option)

However you need to ensure whether as per your solution whether the Code Part 1980 must capture the Other Mandatory Code Part or shou not capture the Blocked Code Part

Thank You