Cannot access EC2 Instance by ssh

Maybe for some of the reason of these changes sshd failed to start.

Did you considered use system manager for access?

Hi aelexanh. Do you mean you changed the SSH port from the default port (22) to 1982? If so, did you also update the inbound rules of the security group for your EC2 instance? Remove the "SSH" type rule (with TCP port range 22), and add a new "Custom TCP" type rule with port range 1982 and the appropriate source.