Why did My IP in Edit inbound rules stop working?

Question

Amazon Web Services

Previously, I always set my IP for SSH in Edit inbound rules. And their firewall blocked all logins from other IPs. except mine.
Today I'm trying to put it - and it won't let me. I can not understand what is the reason?

Answer 1

is the instance basically accessible from the Internet? and Route table is ok? and the problem is exactly in the security group, and not the ssh key? and the IP of the instance has not changed?