Lately we had an issue regarding a Dataguard configuration - quite myesterious.
In dgmgrl there were reported standard errors about broken transport and inability to solve the gap and ORA-16810, which is actually the error, which just tell You, something is wrong (and not what is wrong).
The behaviour was as follows - the apply processes worked ok, so if I restored the archivelogs on the standby, they were applied even up to the current log. But then nothing - so it was clear there was a problem with the transport. But resetting connections was in vain, we also changed some parameters in the dataguard configuration, still nothing.
Finally the right solution was to restart the standby, which was a bit counterintuitive as the transport is mainly the feature of the primary. This was also fortunate, as there was no problem to perform that at once without service disruption.
