Thanks for using Microsoft Q&A !!
I believe you are trying to update the configuration with Postgres Single server sample code and thus getting this error. Instead, you need to use the Postgres Flexible server sample available over here ConfigurationsPutSamples.java which will be similar like below -
public static void configurationCreateOrUpdate(PostgreSqlManager manager,String resourceGroup,String serverName) {
manager
.configurations()
.define("array_nulls")
.withExistingFlexibleServer(resourceGroup, serverName)
.withValue("off")
.withSource("user-override")
.create();
}
Please let me know if that's not the case and you still see issues using SDK to update your flexible server configuration.
Thanks
Saurabh