CLEAR BX LIST

How to fix the CLEAR BX LIST BEFORE CLOSING THE FLIGHT error response

The user tries to close flight and got the error response "CLE​AR BX LIST BEFORE CLOSING THE FLIGHT" like below:

GF908/26DEC/CLOSE/LCLC1Y136/SECOK                                                      

 ET   908 26DEC   KAN      1520   787 BX   LIST      C0Y1                              

  1  YAKUBU     NASIR      H   ADD     F  1                                             

¥CLEAR BX LIST BEFORE CLOSING THE FLIGHT¥    

** Please urgently report the case to SabreSonic helpdesk for this can only be fixed by them**
In your report include:
-flight number
-origin & destination
-date of flight