After replacing the SFTP server where the SpanVA backups were stored, SFTP backups failed with an authentication error.
Test Connection also fails.
When using the same IP address for the new server, the keys for that IP address were stored in known_hosts on the SpanVA. So SpanVA Backup job was not able to connect and throwing know_hosts error when Engineering tried using sshpass -p command on SpanVA.
To use same IP address on a new Server for SpanVA Backups - the old keys for that IP Address need to be removed on SpanVA.
Open a ticket with Technical Support and reference this KB article