CALL_FUNCTION_SIGNON_INVALID is an ABAP runtime error which you may come across when using or developing within an SAP system. See below for the standard details explaining what it means and how you can avoid or fix this runtime error.
Short Dump Classification: I - Internal Kernel Error
You can view further information about a runtme error by using transaction code ST22 which will show you this and all runtime erros that have happen in your SAP system.
Also check out the Comments section below to view or add related contributions and example screen shots.
When making an RFC call for the selected client, enter a valid user ID
and password, and check all call parameters if you are using a
different logon mechanism.
Session-Key.............. <runtime parameter>
Taskhandler-Fehlercode... <runtime parameter>
RFC logon attempt to server unsuccessful.
Please see internal error for more details about the possible cause of this runtime error and how it could be avoided.
An RFC (Remote Function Call) with an invalid user ID was sent from an
external program.
An external program calls function modules with screen output. To allow
this, the JCO or the RFC Library was instructed to open a SAPGUI and to
connect the RFC logon with the SAPGUI logon. This could not be executed
however due to an error.
An RFC call could not be made on the server with the user data provided.
CALL_FUNCTION_SIGNON_INVALID - call function signon invalid CALL_FUNCTION_SIGNON_INTRUDER - call function signon intruder CALL_FUNCTION_SIGNON_INCOMPL - call function signon incompl CALL_FUNCTION_SEND_ERROR - call function send error CALL_FUNCTION_SECSTORE_ERROR - call function secstore error CALL_FUNCTION_RETURN_ERROR - call function return error