Thank you for your reply. I treid to restart listener as well, but it did no make any change - only Linux Cluster restart helps to solve the problem - but this can't be a solution. I think that after a instance reboot something start to go wrong ... but in the same time after reboot instance get registered in the listener.
You need to check your listener.ora file on both the nodes.
Also check with
lsnrctl serv
both nodes should know of the services that are running on each other.
when the instance comes up they should register itself with the listener this is by default if you use the port 1521 or you should use the local_listener and remote_listener parameter in spfile.
Thank you for your reply. Please see attached output.
I am not sure, but I think, SERVICE_NAME = orcltest did not get registered after instance reboot.