The first thing I would do is make sure that your key pair is OpenSSH compatible. For example, this is one of my public keys and yours most likely looks the same:
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDLmqjzH1lJ+uTlL2yGjyOcFKdxYFWYLSUdqN5LMRA1YiXHJvTkOo4Ky8w8NmNqJoKwLhxESLNpdUteZbacCRf3I9j57td8IaySk3LFpNK1waDwPcwFlvOv6NtKdwFsgQ0CUqJ6Ya9AUVfTlyePBhH9lKy7gnsloAtHOfGlHdCt5X5f2iB0WU/PPZZskfj79z84dlUPrdfdq8DZmOQDnTEF6XnqaYIqrYXKnPOTovCnOGrc1xJjV+UQ7dZhc/5UCECDK8DEUKZ21aK5htCwhqQFLVV4M6SB7/mDiWXvNx79hKuHDHsHCv6L4YuqHkHAGNtmHq2UxntJ9K6i0DxoMq/1 jarlanddonnell@Jarlands-iMac.local
If all is well there, I would add the verbose flag to your SSH connection (ssh -vvv) and go over each line to see what it is doing. If it loads your private keys without error and moves forward without accepting login, I would suggest one of these is true:
- The server has been configured to not allow the login at all.
- The server is not loading an authorized_keys file that contains your public key.
I couldn’t say for sure which configuration had been changed to cause #1, but #2 should be fine if the public key is on a single line in authorized_keys under /root/.ssh or /home/username/.ssh (if not using root). More than likely I’ve already covered the problem area, taking a closer look at each detail should reveal something that you have not yet noticed. SSH login issues tend to not be very complex at their core.