Worked yesterday - failing today
I changed to a non-standard port, 1527, and made sure local_listener was defined on both servers.
Stopped and started the listeners and DG didn't work. Disabled and enabled configuration and still nothing.
So I shut down the listeners and put the port back to 1521. Still no luck. When I do the disable/enable via DGMGRL on the primary there is a lot of activity on the standby in the alert log and dr log. When I try to ship a log file from the primary to the standby I now get: