You should probably run
select utl_http.get_detailed_sqlerrm from dual;
Just beware - it isn't a general purpose function, works for UTL_HTTP errors only. For example, it won't work for SQL errors:
SQL> select deptno, min(sal) from emp;
select deptno, min(sal) from emp
*
ERROR at line 1:
ORA-00937: not a single-group group function
SQL> select utl_http.get_detailed_sqlerrm from dual;
GET_DETAILED_SQLERRM
--------------------------------------------------------------------------------
... nor for PL/SQL errors:
SQL> begin
2 select empno from emp;
3 end;
4 /
select empno from emp;
*
ERROR at line 2:
ORA-06550: line 2, column 3:
PLS-00428: an INTO clause is expected in this SELECT statement
SQL> select utl_http.get_detailed_sqlerrm from dual;
GET_DETAILED_SQLERRM
--------------------------------------------------------------------------------
SQL>
... but would work for UTL_HTTP-related errors:
SQL> declare
2 l_request utl_http.req;
3 begin
4 l_request := utl_http.begin_request('http://www.some_company.com');
5 end;
6 /
declare
*
ERROR at line 1:
ORA-29273: HTTP request failed
ORA-06512: at "SYS.UTL_HTTP", line 1130
ORA-24247: network access denied by access control list (ACL)
ORA-06512: at line 4
SQL> select utl_http.get_detailed_sqlerrm from dual;
GET_DETAILED_SQLERRM
--------------------------------------------------------------------------------
ORA-24247: network access denied by access control list (ACL)
SQL>