Can't SSH Into EC2 Instance
Solution 1:
The only thing I see in that log is roaming not allowed Are your keys type 1 or type 2?
Also check permissions on /Users/tigger/.ssh directory which should be owned by the user and be chmod 700. The authorized_keys file should also be chmod 700 and owned by the user.
Solution 2:
Are you trying to log in with the right user? The Ubuntu images use the ubuntu user instead of root for example.