A SAPJOB job is not triggered with following errors
%CASAP_E_990 RFC error operation/code: RfcOpenEx
%CASAP_E_991 Key: RFC_ERROR_LOGON_FAILURE
%CASAP_E_993 Message: Timeout
Apart a real issue with the userid/password in SAP, another possible reason might be due to lack of SAP dialog processes.
This situation is addressed in SAP where you can ask the SAP administrator to increase the number of Dialog processes from SM50 transaction in SAP GUI.