Unbound doesnt start

The error messages show that having disabled IPv6 caused the problem.

Dec 29 16:01:04 mail unbound[59226]: [1514559664] unbound[59226:0] error: can't bind socket: Cannot assign requested address for ::1
Dec 29 16:01:04 mail unbound[59226]: [1514559664] unbound[59226:0] fatal error: could not open ports

IPv6 really isn't optional anymore. It hasn't been for a while. The best thing to do, of course, is to not disable IPv6 on the system.

If you can't do that for some reason, then check your unbound.conf for interface and control-interface directives that specify IPv6 addresses and remove them. Note that the default for control-interface is to listen on both 127.0.0.1 and ::1, so you'll have to specify it explicitly if you don't want ::1.