Hello Alice,
unfortunately the SLG1 errorlog entry only points to a general error handling method. So analysing the actual reason of the error would require additional debugging.
As I haven't seen a lot of KW related errors in TREX lately could you share some details on your SAP eRec release, TREX release and the interface technology (are you still using the Python extensions ehre KW issues were a common issue while they more or less disappeared with the SES interface).
Kind Regards
Roman