Several distros refuse to accept a root login via ssh, so maybe that's the reason.
Try to ssh as user (orangepi most certainly) and then try to issue a sudo command. If you're successful that means that your distro is not accepting root login, which is a good thing in most cases.
Besides, being always logged as root is not a good thing I'd say!
And guess what: It's explained on several locations and especially as part of the 'Quick Start' tab on download page: https://www.armbian.com/orange-pi-zero/