can't connect lightsail terminal both connect using ssh and local computer with ssh key

Hello!

Here are some troubleshooting steps you can consider:

• Ensure that your Lightsail instance is running.
• Make sure that SSH (port 22) is allowed with "Allow Lightsail browser SSH" option for your case.
• Ensure that you are using the correct private key that corresponds to the public key associated with your Lightsail instance.
• Did you try in another network? Sometimes, network interruptions or strict corporate firewalls can interfere with SSH connections.
• Did you try another browser?

I hope this helps! If this solution works for you, please accept the answer. Otherwise, do leave a comment, and I'll try to assist you with other ideas.

Vitor's prior suggestions look sound. One consideration is this -- is your instance currently functional? If not, you may be breaching your CPU credits and causing your instance to throttle which will interfere with its various tasks including ssh. You can check on this by following this documentation: https://lightsail.aws.amazon.com/ls/docs/en_us/articles/amazon-lightsail-viewing-instance-burst-capacity