Currently on the App Platform, attempts to call external servers via SFTP/FTP are not allowed (per technical support). The response to these attempts is currently a timeout after 4 minutes, likely because the request is just ignored and not responded to. For people like myself who missed that line in the documentation, would be VERY nice to get an immediate response that that request type is not allowed so we do not spend days looking at Firewall and other settings. This extends to any other requests (SSH/SSL) that may be ignored.