Hi Valentina,
Never seen this message before as a starting point.
What do you see at physical level in SE16 for CATSDB for those ****? If I remember that correctly for NWA you will not find a 4 digit code, it is an indirect reference (similar to the object number). Theoretically it could have been deleted and new NWA created with the same external number 9720?!
Can you delete the whole line, save and re-create it again?
Also you can try to add a new line with the same account assignment, just to test if that will pass through.
Because if we assume the message is false, then it can be either OSS or message to SAP.
Regards,
Paulo