How to fix warning about ECDSA host key here

Tia@DESKTOP-18RKIM8 MINGW64 ~
$ ssh [email protected]
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
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:iJ9W16xK/HKi+Xilixgt3Fv1MRPIRF7L4W7U+x2Z9EU.
Please contact your system administrator.
Add correct host key in /c/Users/Tia/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /c/Users/Tia/.ssh/known_hosts:11
ECDSA host key for 10.0.0.36 has changed and you have requested strict checking.
Host key verification failed.

#Remove the cached key for 10.0.0.36 on the local machine:

Tia@DESKTOP-18RKIM8 MINGW64 ~
$ ssh-keygen -R 3.231.244.225
ssh-keygen -R  3.143.184.59
ssh-keygen -R server3.anomicatech.com


# Host 10.0.0.36 found: line 11
/c/Users/Tia/.ssh/known_hosts updated.
Original contents retained as /c/Users/Tia/.ssh/known_hosts.old

Nginx manage bad gateway issue

Bad Gateway at Admin

Tia@DESKTOP-18RKIM8 MINGW64 ~/Downloads
$ ssh -i "DEL-key.pem" [email protected]
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
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:zu6dFAMdwnzGU4pD/LnIL9aONqXKqLYzZuZ52IN+rdE.
Please contact your system administrator.
Add correct host key in /c/Users/Tia/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /c/Users/Tia/.ssh/known_hosts:64
ECDSA host key for ec2-3-231-244-225.compute-1.amazonaws.com has changed and you have requested strict checking

ssh -i "DEL-key.pem" [email protected]

ssh: connect to host localhost port 22: Connection refused in |Ubuntu | Error | Resolved here

sudo apt-get install ssh