Schema level trigger

XYZDBA is the owner of all the tables in a schema called XYZ.

I have created public synonyms for all these tables.

I have created USER1 who has alter/insert/update/select/reference priviliges on the public synonyms created above.

I have a schema level trigger like

CREATE OR REPLACE TRIGGER XYZDBA_logintrig
AFTER LOGON ON XYZDBA.SCHEMA
DECLARE
      /* variable declarations-------start*/
      ssn number(8)  ;
      hst varchar(30) ;
      logtime varchar(10);
BEGIN
      select sys_context('USERENV','SESSIONID') into ssn from dual;
      select sys_context('USERENV','HOST') into hst from dual;
      select to_char(SYSDATE,'HH24:MM:SS') into logtime from dual;
      insert into  XYZDBA.Audloginlogs(user_id,session_id,host,logon_day,logon_time)
            values (user,ssn,hst,to_date(sysdate),logtime) ;
END ;

XYZDBA has administer database trigger system privilige.

Whenever USER1 logins in I want the trigger to create a row in audloginlogs table ?

Whenever I login as XYZDBA a row is getting created . But, when I login as USER1 the row is not getting created .

What am I  doing wrong ?

regards
jana