It might be this:
But if you are patched at all probably not.
This is also worth a look:
Redo log shipping fails with ORA-270 at Primary when max_connections is set to value > 1 (Doc ID 2042222.1)
What other error messages exist on the primary and the standby alert log files ?
On the primary can you run this and look out the reason for the remote archival failure ?
On the primary:
SQL> select severity,error_code,message from v$dataguard_status where dest_id=2;
Assuming that log_archive_dest_2 is configured on the primary to ship the redo to the standby
-- Shivananda Rao
Try to check network connection in between primary and standby (test for any network packets are getting dropped). Make sure you have good network connection.
- Pavan Kumar N