I am also having the same issue. My gateway clusters are both online and I have gateway connection to an Oracle host, in one of the gateway cluster I have an established connection to the Oracle host and the other cluster it is showing as Partially Online, what does this mean? Need help. I have users that are trying to refresh their datasets and continuously receive an error.
You might encounter any of several errors from Oracle when the naming syntax is either incorrect or not configured properly:
ORA-12154: TNS:could not resolve the connect identifier specified.
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor.
ORA-12541: TNS:no listener.
ORA-12170: TNS:connect timeout occurred.
ORA-12504: TNS:listener was not given the SERVICE_NAME in CONNECT_DATA.
These errors might occur if the Oracle client either isn't installed or isn't configured properly. If it's installed, verify that the tnsnames.ora file is properly configured and you're using the proper net_service_name. You also need to make sure that the net_service_name is the same between the machine that uses Power BI Desktop and the machine that runs the gateway. For more information, seeInstall the Oracle client.
You might also encounter a compatibility issue between the Oracle server version and the Oracle Data Access Client version. Typically, you want these versions to match, as some combinations are incompatible. For instance, ODAC 12.x does not support Oracle Server version 9.