When establishing an SSH connection, the error "Server host key did not match the signature supplied" in AWS indicates an essential security problem. This error occurs when the host key provided by the server does not match the signature saved in the client, indicating a potential communication channel compromise. Host key verification is a critical component of SSH security, functioning as a way to authenticate the server reliability.

This problem requires rapid repair in AWS setups where safe and reliable communication is critical. Understanding and correcting the causes of this disconnect is essential for maintaining the integrity of connections and protecting against potential unauthorized attacks.

You can solve this issue by taking the following steps:

Verify Server Identity:

Ensure that you're connecting to the right server. Check the remote server public key.

Check the Server Configuration:

Check that the SSH configuration on the server matches your expectations. Changes in the server SSH settings may result in the display of a different host key

Update Host Key:

If the server host key is changed, PuTTY will detect the mismatch. Accept the new key and authorize the request to update the stored host key

Check the Server Configuration:

Check that the SSH configuration on the server matches your expectations. Changes in the server SSH settings may result in the display of a different host key

Analyze Security Events:

Examine system logs or AWS Console events for any security-related events or server configuration changes that could explain the host key difference.

Reset the Host Key:

Consider resetting the host key on the server side and updating your client accordingly in more controlled conditions where you can coordinate with the server administrator.

It is essential to effectively resolve the "Server host key did not match the signature supplied" error in AWS to be able to maintain secure and authorized connections. Resolving host key mismatches as quickly as possible is essential for reducing security concerns and ensuring the integrity of communication. 

Establishing connection between Windows EC2 Instances and RDS Databases with PuTTY.