I had the same problem after testing Visual Studio Code with remote-ssh plugin. During the setup of the remote host the software did ask me where to store the config-file. I thought a good place is the '.ssh-folder' (Linux-system) as it was a ssh-remote configuration. It turned out to be a bad idea. The next day, after a new start of the computer I couldn't logon via ssh on the remote server. The error message was 'Could not resolve hostname:....... Name or service not known'. What happen was that the uninstall from VSC did not delete this config-file and of course it was than disturbing the usual process. An 'rm' later the problem was solved (I did delete this config-file).