DBT-16095
Data Guard protection mode 'string' and transport mode 'string' can not be updated on database 'string'.
Cause
It is required to have minimum one standby database in synchronous transport mode (SYNC or FASTSYNC) in order to have Data Guard protection mode as MAX_AVAILABILITY.
Action
Either update the standby database transport mode to SYNC or FASTSYNC, or update the Data Guard protection mode.