I ran into this message working to establish a Hyper-V VM to evaluate/train on the APEX 19 platform, however the Google responses to a search on the message were overlooking a more basic cause, so I thought I'd leave this suggestion here for someone else along this path.
Update IP addresses at the following locations:
C:\OracleHomes\18c\18cSoftware\network\admin\listener.ora
C:\OracleHomes\18c\18cSoftware\network\admin\tnsnames.ora
C:\ords\params\ords_params.properties
C:\ords\ordsconfig\ords\defaults.xml
Since my Hyper-V runs on both my office and home networks it is configured for dynamic IP addressing, and because I am working to learn the environment and platform I have been frequently restoring the environment from previously archived milestones.
That means that frequently the new VM comes into the environment with a new IP. (Note: I tried <localhost> parameters in one iteration, however I personally found that calling the ip address implicitly made for a more stable behavior in the virtualized image.)
So ... using a text-editor, I opened each of the files listed above and updated the IP address parameter. Specifically (File:Parameter):
listener.ora : HOST = <ip address>
tnsnames.ora : HOST = <ip address>
ords_params.properties : db.hostname = <ip address>
defaults.xml : <entry key="db.hostname"> ip address </entry>