This error often appears when using wsadmin.

~]# /opt/WebSphere/AppServer/profiles/profile1/bin/wsadmin.sh

WASX7023E: Error creating "SOAP" connection to host "localhost"; exception information: com.ibm.websphere.management.exception.ConnectorNotAvailableException: [SOAPException: faultCode=SOAP-ENV:Client; msg=Unable to find a valid IP for host localhost]

Notice in this example that profile profile1 is being used.

• If the profile is a WebSphere Network Deployment Manager, ensure the deployment manager is up and running. Check out my article Start Stop or Restart a network deployment manager.
• If the profile is a WebSphere Application Server, ensure the application server is up and running. Check out my article Start Stop or Restart an application server

Assuming profile1 is up and running, the SOAP hostname and port for profile1 will be listed in profile1 serverindex.xml file, which is located at ${WAS_INSTALL_ROOT}/profiles/profile1/config/cells/<cell name>/nodes/<node name>/serverindex.xml. In this example, the hostname for profile1 is server1.example.com and the SOAP port is 12345.

<specialEndpoints xmi:id="NamedEndPoint_123456789" endPointName="SOAP_CONNECTOR_ADDRESS">
  <endPoint xmi:id="EndPoint_123456789" host="server1.example.com" port="12345"/>
</speicalEndpoints>

Or if you are using the WebSphere admin console, 

• If the profile is a WebSphere Network Deployment Manager, the SOAP port will be listed at System administration > Deployment manager > Ports and will be listed as SOAP_CONNECTOR_ADDRESS.
• If the profile is a WebSphere Application Server, the SOAP port will be listed at Server types > WebSphere application servers > your application server > Ports and will be listed as SOAP_CONNECTOR_ADDRESS.

Ensure the ${WAS_INSTALL_ROOT}/profiles/profile1/properties/wsadmin.properties file for profile1 has the SOAP hostname and port listed in the serverindex.xml file.

com.ibm.ws.scripting.connectionType=SOAP
com.ibm.ws.scripting.port=12345
com.ibm.ws.scripting.host=server1.example.com

Now try to reissue the wsdamin.sh command and if all goes well, hopefully you will no longer get the "Error creating SOAP connection to host" error.

~]# /opt/IBM/WebSphere/AppServer/profiles/profile1/bin/wsadmin.sh