Plesk becomes unavailable as soon as I add a domain.

This issue appears to be related to how Plesk handles domain configuration and SSL certificates when you add a new domain to your Lightsail instance.

When you attach a static IP to your Lightsail instance and then add a domain in Plesk, the system may still be using the old configuration with the default Plesk URL, causing the HSTS errors and connection issues you're experiencing.

Here's how to resolve this:

1. First, try stopping and restarting your Lightsail instance. This sometimes refreshes the configuration and fixes the issue.

2. If restarting doesn't work, you can run the following command to enable access to your Plesk admin panel using your static IP:

sudo plesk bin admin --enable-access-domain "your-static-IP"

Replace "your-static-IP" with your actual static IP address.

3. After running this command, you should be able to get a one-time login URL for your Plesk instance.

4. Make sure ports 443 and 8443 (which Plesk uses) are accessible and not being blocked by any firewall settings.

5. If you're still experiencing issues, you might need to check Plesk's configuration files or consider repairing the Plesk installation more thoroughly.

Plesk is a control panel that allows you to manage web hosting environments on your Lightsail instance, and these types of configuration issues can occur when adding domains or changing network settings.
Sources
Troubleshoot Plesk login errors | AWS re:Post
Virtual Private Server and Web Hosting – Amazon Lightsail Resources – Amazon Web Services
Virtual Private Server and Web Hosting – Amazon Lightsail Features– Amazon Web Services

Hi, I believe the issue stems from hostname resolution conflicts when a static IP is attached.

When a static IP is attached, the initial ####################.plesk.page would fail to resolve properly.

Solutions to try:

1. Access via Static IP directly:
   • Use https://<your-static-ip>:8443 to access the Plesk admin panel
2. Update Plesk's IP configuration:
   • Follow official Lightsail guide: https://docs.aws.amazon.com/lightsail/latest/userguide/set-up-and-configure-plesk-stack-on-lightsail.html#attach-static-ip.
   • Go to Tools & Settings → IP Addresses → Update public IPs
   • After updating, Plesk will generate a new hostname: #######new############.plesk.page. Use this new hostname to access Plesk.

You should be able to connect to the Plesk admin page using either method.

Note: you might see a browser warning that your connection is not private, not secure, or that there's a security risk. This happens because your Plesk instance's SSL/TLS certificate applied to it doesn't match the new public IP being used. In the browser window, choose Advanced, Details, or More information to view the options that are available. Then choose to proceed to the website even if it's not private or secure.