Problem:

The following error occurs when connecting to an SFTP host for the first time:

This error is most commonly seen in Linux environments.

Root Cause:

The Host key is not accepted by your system.

Solution:  

The new Everbridge host key must be accepted and saved to your known-hosts file. Once you accept the host key, it will be saved to your known_hosts file, and will be used to verify all subsequent connections.