Oracle: Error in converting DateTime to Epoch

While trying to convert datetime to epoch, I am getting an error: ORA-01810: format code appears twice

QracleSQL query:

select (trunc(TO_TIMESTAMP('2022-05-08T19:09:17Z', 'yyyy-MM-dd"T"HH:mm:ssXXX')) - TO_DATE('01/01/1970', 'MM/DD/YYYY')) * 24 * 60 * 60 from dual;

>Solution :

Format mask is incorrect.

SQL> select trunc(cast (to_timestamp('2022-05-08T19:09:17Z', 'yyyy-MM-dd"T"HH24:mi:ss"Z"') as date)
  2        - to_date('01/01/1970', 'mm/dd/yyyy')) *24 *60 *60 res
  3  from dual;

       RES
----------
1651968000

SQL>