I use VPS from DigitalOcean.
First generated SSH key: ssh-keygen -t RSA . Then he added it to the Security of the Droplet himself, having previously coping it in this way: cat ~ / .ssh / id_rsa.pub
When connected by SSH root @ [Your.IP.Address.here] throws out an exception:

Host Key Verification Failed

because of what it can be?

Answer 1, Authority 100%

When connected by SSH root @ [Your.IP.Address.here] ejects – host key verification failed . Why could it be?

due to the fact that the cast (fingerprint ) key to which the second side ([Your.IP.Address.here] ) offers to encrypt the data, does not coincide with Saved Slept.

Perhaps the key change to the second side is somehow connected with your actions – added it to the SECurity of the Droplet itself . I have no idea what it is for “droplet”, and that he may have for “Security”, but If you are sure , that it should have been, you can remove the previous saved cast:

$ ssh-keygen -r [your.ip.address.here]