ON-ERROR Trigger displays error two times

Hi,

In Oracle Forms 12c

I have written this code in ON-ERROR trigger:

BEGIN

  IF DBMS_ERROR_CODE = -28001 THEN

       Message(DBMS_ERROR_TEXT);

       :GLOBAL.pwd_ch:=1;

       RAISE FORM_TRIGGER_FAILURE;

  ELSIF DBMS_ERROR_CODE = -24309 THEN

       NULL;

       RAISE FORM_TRIGGER_FAILURE;

  ELSE

       Message(DBMS_ERROR_TEXT);

       RAISE FORM_TRIGGER_FAILURE;

  END IF;

END;

The problem I am facing is:

Suppose I have entered an incorrect Connect String.

The form gives error message ORA-12154 TNS could not resolve the connect identifier specified.

I click OK.

It will again prompt the Login screen, this time I enter all the credentials correctly