SSH Connection works, Deployment error host unknown

When setting up an sftp connection to the google cloud, the ssh connection (OS X, host config given in file ~/.ssh/config) works fine, that is the connection test succeeds, but the deployment and the project interpreter cannot connect, I always get a message "unknown host".  The is a similar post from 2018 (see link below) but no solution given. I tried deleting and removing the connection, disabling and reenabling the proxy, but nothing helps. Any idea what is going on?

https://intellij-support.jetbrains.com/hc/en-us/community/posts/360000543359-Deployment-SFTP-test-fails-but-SSH-connection-succeeds?input_string=SSH%20Connection%20works%2C%20Deployment%20error%20host%20unknown