If you’ve rebuilt a server and suddenly SSH refuses to connect with a “Remote Host Identification Has Changed” warning, don’t panic. This is a very common and expected situation when working with VPS servers, cloud instances, or rebuilt environments.
In this guide, I’ll explain what the error means, why it happens, and how to fix it safely using a single command.
What This SSH Error Means
When you connect to a server over SSH for the first time, your computer saves a fingerprint of that server’s identity. This fingerprint is stored locally so SSH can verify that you’re connecting to the same trusted server in the future.
If the server is rebuilt, reinstalled, or replaced—but keeps the same IP address—its fingerprint changes. When SSH notices this mismatch, it stops the connection and displays this warning to protect you from possible impersonation attacks.
In short:
- Your computer remembers the old server
- The server was rebuilt or replaced
- SSH detects a mismatch and blocks the connection
This is normal behavior and a sign that SSH security is working as intended.
Common Reasons You’ll See This Error
You’ll usually encounter this message after:
- Rebuilding or recreating a VPS
- Deleting and recreating a cloud instance
- Reinstalling the operating system
- Restoring a server from a snapshot
- Reusing the same IP address on a new server
If you expected the server to change, this warning is harmless.
The Fastest & Safest Fix
The fix is to remove the old fingerprint from your computer so SSH can trust the new one.
Run this command on your local machine (not the server):
ssh-keygen -R 1.1.1.1 Replace 1.1.1.1 with your server’s IP address or hostname.
What this command does:
- Finds the stored fingerprint for that IP
- Removes it from your local SSH records
- Leaves everything else untouched
After running it, reconnect using SSH:
ssh -i your-key.pem username@1.1.1.1Note
This SSH command format is commonly used on AWS (Lightsail / EC2) and other VPS providers that use key-based authentication.
Depending on your hosting provider:
- Your SSH username may be different (for example:
root,ubuntu, orbitnami) - You may not use a
.pemkey file at all - Some hosts allow password-based SSH instead of key files
Always refer to your hosting provider’s official SSH login details.
When prompted during reconnection, type yes to trust the new server fingerprint.
Where SSH Stores These Fingerprints (Windows)
On Windows, SSH stores known server fingerprints in this file:
C:\Users\YourUsername\.ssh\known_hostsEach line represents a server you’ve connected to before.
The ssh-keygen -R command simply edits this file for you.
