Warning: Remote Host Identification has Changed

Using terminal program on Apple Mac book pro I had following error when connecting to a Linux server

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@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
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IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:8wZ3n0MN2c1YzOdYZ01Ct+MVDm924tmfw4NUfAnMenA.
Please contact your system administrator.
Add correct host key in /Users/neil/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/neil/.ssh/known_hosts:6
ECDSA host key for 192.168.1.1 has changed and you have requested strict checking.
Host key verification failed.

The server had been recently rebuilt with revised ssh server configuration.

I opened another terminal session and edited the file .ssh/known_hosts using vi.

192.168.1.1 ecdsa-sha2-nistp256 MIGeMA0GCSqGSIb3DQEBAQUAA4GMADCBiAKBgGacCUIonaql4oszZ1QFBxDxVD898cZH+UaPglM71NSad9b5MBHcTIOVEHNjSj7BBW3YMxI45fvg/He8zA94IJw1LR84zz1JwfmtEmD4VWt9pw8KRKmFKRI7X+rvsCknRJcpOHC7GQqYD4IHU6kzIqBNAfMn6YGzRo7XXhxgmwkbAgMBAAE=
192.168.1.78 ecdsa-sha2-nistp256 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCVoNuBxLq4QKwcYhXh06PU7LQHCKSdQEbEVUzEIZS46dCjrIosp73+ulbqfUGPG4GlduKG98CzdijoFS2t+C9Kq3A48uMxdPRfhhOCutWl+fLmLY2G7WgM+/8nAB07SQhtgNeNH55TCvOlsrkaEGdsek1ZePNsJbiRRL+UCG7sJQIDAQAB
192.168.1.174 ecdsa-sha2-nistp256 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCFzyPNE4K/g55XU2fV3vNZNv/A6EE26zB1VLmiZPGFJpqJdLsvwSFiQx0T4LOJMoCXxiCjiyexd5hQyh0s3euWBWdn25TmsNToMmRosrkbfJGnKYj12ZUTuuOIgVwfxlAroHmf7m0gl+Yx43s7eeXVRn2cnwCHziZN2E5X+RqoowIDAQAB
192.168.1.52 ecdsa-sha2-nistp256 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCHaOo07u4NFIBQxMenPfKSjV06+77TEgaWhiyvoIpQvP0udBVbvJuOD3EpBXLNDV9Z4jeCofrqy4mJRqP08Wq/r6EFny8i34EQm/VJNzLqvNhJ76JzVaYJYmL/CSKGklHjYGktUCq4rHTcxoUlcL9uvfXO2raWsnOFgBIZJt/KzwIDAQAB

Deleting the previous entry for the server and ssh to the server once more.

ssh 192.168.1.1
The authenticity of host '192.168.1.1 (192.168.1.1)' can't be established.
ECDSA key fingerprint is SHA256:8wZ3n0MN2c1YzOdYZ01Ct+MVDm924tmfw4NUfAnMenA.
Are you sure you want to continue connecting (yes/no)?

I selected yes and was able to access

Interesting – my computer (Debian) has these entries encrypted.