The Dashboard import error is unrelated to those ones.
Are you using SSL authentication? Unfortunately that's not supported in the Extention Manager (although we are planning to support that sometime soon). For now you can use the extension packages user/password authentication.
Seems like the dependency sshpass is missing. (`apt install sshpass` will install it on a Debian-like system). If you already installed it, it might be the same authentication issue as above.