First configuration looked like this:
create configuration 'DGConfig' as primary database is orcl_site1 connect identifier is orcl_site1 ; add database orcl_site2 as connect identifier is orcl_site2 ; enable configuration ;
Everything finished successfully,
show configuration showed nice output. BUT after a while it stopped to work, I got an error on the standby database. Nothing worked, I could not
switchover to orcl_site2, but
show database verbose orcl_site[1,2] gave good information, real time apply worked (tablespace created/dropped).
So I removed the configuration and added all 4 orcl_site[1,2] from the configuration between single quotes and now everything works.