You are speaking about different things.
1.
TNS-03505: Failed to resolve name
means that one or more of the components are not correct: host name, port name, instance_name, protocol or there is a firewall between the server and host (happens often in Windows environment).
2.
oracle initialization or shutdown in progress
is different thing. It is caused by miscommunication between the client and server.
First check if the server is running and the instance is registered by the listener of the server machine:
# lsnrctl status
# lsnrctl services
The database is running if you can connect to it (e.g. SQL*Plus, SQLDeveloper, TOAD)
The v$instnace and v$database views will show you the current state of the instance and when it is started..
In some cases this statement is also triggered by unregistered by the listener DB. I have published many times how to register the instance by the listener, so you are welcome to find and use these postings.
