Unable to connect via SSH to AWS Lightsail instance created from snapshot

Question

I am having the exact same problem, I tried:

1. From the UI:
   1.1. Create instance from automatic snapshot.
   1.2. Create instance from manually created snapshot.

2. From the CLI:
   2.1. Create instance from manual snapshot also trying to disable the firewall like this answer: SSH back to AWS Lightsail after UFW enabling

3. Creating different static IPs for the new instance.

4. Using different SSH key/pairs (default & new) in instance creation.

5. Recreating firewall rules from the UI.

6. Rebooting the instance.

The result of aws lightsail get-instances is:

{
  "name": "Wordpress-Spain",
   ...
   "ports": [
     {
      "fromPort": 22,
      "toPort": 22,
      "protocol": "tcp",
       "accessFrom": "Anywhere (0.0.0.0/0)",
       "accessType": "public",
       "commonName": "",
       "accessDirection": "inbound",
       "cidrs": [
         "0.0.0.0/0"
       ],
     },
  ...  }

while nmap throws:

PORT    STATE  SERVICE
22/tcp  closed ssh
80/tcp  open   http
443/tcp open   https

According to the Lightsail UI & AWS CLI everything is ok, but I consi

An error occurred and we were unable to connect or stay connected to your instance. If this instance has just started up, try again in a minute or two. UPSTREAM_NOT_FOUND [519]

Answer 1

To reproduce your situation, I did the following:

• Launched an Amazon Linux 2 instance in Amazon Lightsail
• Connected via SSH and created a file on the instance (for testing purposes)
• Created a Manual Snapshot of the instance
• Launched a new instance from the Snapshot (with all default settings)
• Connected to the new instance via SSH (clicking on the SSH icon in the console)
• Displayed the contents of the test file -- it matched!

The above steps were all done with default settings. It worked fine for me!

I then repeated the above using a WordPress blueprint. I was able to login to the second instance just fine.

So, it doesn't look like a Lightsail problem. It likely has to do with something that has been changed/configured on the operating system.