I'm experiencing an issue with my AWS Lightsail instance where I am unable to connect, and I receive the following error message:
"Unable to connectIf the instance has just started up, wait a few minutes and try again. If this continues, you can try to connect to your instance by using a third-party SSH client such as PuTTY.UPSTREAM_NOT_FOUND [519]"
I've tried waiting for a few minutes after starting the instance, but the problem persists. I've also attempted to connect using a third-party SSH client like PuTTY, but without success.
What could be causing this error, and what steps can I take to resolve it? Additionally, are there any specific configurations or settings I should check to ensure that the instance is accessible? Any guidance on this issue would be greatly appreciated.
I have tried rebooting the instance, stopping and restarting it, as well as removing and re-registering the key pair.