We have this seen this happen more than a few times with our Mac customers using their built-in SSH CLI client utility.
This is a client-side issue, and is generated when your client connects to different servers using the same AWS IP address.
For example, say you deploy aMiSTACX for Magento with EIP Address: 32. 32. 1. 5, and connect via SSH for the first time.
You will cache a fingerprint to the local Mac SSH client.
Then you decide to switch the AWS EIP to another server, and establish another SSH connection.
Note: WinSCP users you get a simple Yes/No warning about the fingerprint.
For Macs with a certain security setting [Strict SSH Checking], you will need to clear the fingerprint from the previous connection.
Remove the cached key for the IP address on the local machine as follows:
ssh-keygen -R {AWS IP ADDRESS}
e.g., ssh-keygen -R 32.32.1.5
and then just try the connection again:
ssh -i path/to/AWSAccessKey.pem ubuntu@32.32.1.5
or
ssh -i “AWSAccessKey.pem” ubuntu@32.32.1.5
Should be success? What can I say – it’s a Mac.
~Lead_Robot