Lightsail SSH connect timing out

It sounds like you're experiencing intermittent SSH connection issues with your Lightsail instance. This can be frustrating, especially when you're paying for a service you can't consistently access. Here are some potential causes and troubleshooting steps:

1. Firewall or Security Group Settings: Verify that port 22 (for SSH) is open in your instance's firewall settings. Sometimes, these settings can change unexpectedly.

2. Instance Resource Usage: High CPU or memory usage can impact SSH responsiveness. Check your instance's resource metrics in the Lightsail console to see if there are any spikes or consistent high usage.

3. OS-level Firewall: The issue might be caused by a firewall on the Lightsail OS side. You could try running a startup script when restarting your instance to disable the firewall and reset iptables:

   sudo ufw disable sudo iptables -F sudo mv /etc/hosts.deny /etc/hosts.deny_backup sudo touch /etc/hosts.deny sudo systemctl enable sshd sudo systemctl restart sshd

4. System Logs: When you can access the instance, check the OS system logs. Look for any errors or warnings related to SSH connections or system issues that might be causing the timeouts.

5. Instance Size: If you're consistently experiencing high resource usage, you might need to upgrade to a larger Lightsail plan.

6. Data Recovery: If you continue to have issues, consider creating a snapshot of your instance's root volume. This will allow you to recover your data and potentially attach it to a new, functioning instance.

If these steps don't resolve the issue, it may be worth contacting AWS Lightsail support for further assistance, as there could be underlying issues with the instance or the host system that aren't visible to you as a user.

Remember, intermittent issues can be challenging to diagnose, so consistent monitoring and logging when the problem occurs can be helpful in identifying the root cause.
Sources
Lightsail instance keeps timing out | AWS re:Post
Lightsail AWS Can't Access SSH on browser | AWS re:Post
Can not connect to lightsail server even on web ssh, port is open | AWS re:Post

Hi,

In addition to the steps mentioned by re:Post Agent, you could also try these steps:

1. Try rebooting the instance from the Lightsail console. This is the least disruptive solution and maintains the same public IP.
2. If the instance remains unreachable after reboot then stop and start the instance. Note: This will change your public IP address unless you're using a static IP.
3. Monitor the instance's health. Check CPU utilization metrics in the Lightsail console. High CPU utilization for extended periods might indicate need for upgrade. Check system logs if available.
4. If issues persist, consider upgrading your instance, take a snapshot of your current instance and create a new, larger instance using this snapshot.

Relevant Documentations that you may find helpful:

• Troubleshooting connection issues: https://lightsail.aws.amazon.com/ls/docs/en_us/articles/troubleshooting-ssh-issues-in-amazon-lightsail
• Creating snapshots: https://lightsail.aws.amazon.com/ls/docs/en_us/articles/lightsail-how-to-create-a-snapshot-of-your-instance
• Upgrading instances: https://lightsail.aws.amazon.com/ls/docs/en_us/articles/upgrade-virtual-server-machine-in-amazon-lightsail

Thank you.