Plesk

• FAQ
  • Manage Plesk Mailbox Within PanelAlpha
• Troubleshooting
  • Issues with SSO to Plesk
  • Issues with Disk Quota Exceeded
  • Error: The 'wp-config.php' File Already Exists

This page covers common Plesk-related issues in PanelAlpha.

FAQ

Manage Plesk Mailbox Within PanelAlpha

Question: Can Plesk mailboxes be managed within PanelAlpha?

Answer: Yes. Users can manage Plesk mailboxes within PanelAlpha if the Email Server is set to Plesk's internal server in the plan configuration. This setting will apply only to new services.

Troubleshooting

Issues with SSO to Plesk

Problem: The Log In to Control Panel button in the Client Area opens a URL, but the user is not logged in — Plesk shows the standard login form instead.

Symptoms:

1. Clicking Log In to Control Panel (or Login to Control Panel in Developer Settings) opens Plesk, but the user must enter credentials manually.
2. The PanelAlpha API call POST /server-accounts/{id}/control-panel-sso-url succeeds and returns a URL (no error in the Client Area).
3. The same behavior may occur for phpMyAdmin SSO on Plesk, because both features use Plesk session tokens.
4. Important: If one-time login links generated by Plesk itself also fail, the issue is on the Plesk server configuration — not in PanelAlpha. Whitelisting PanelAlpha server IP for Plesk API access does not fix browser-based SSO.

How PanelAlpha SSO works:

PanelAlpha calls the Plesk XML API method server.create_session for the subscription owner, then redirects the browser to:

https://your-plesk-server:8443/enterprise/rsession_init.php?PLESKSESSID={token}

Plesk binds this session to the client's IP address. If session IP validation is too strict (common behind reverse proxies, Cloudflare, or dynamic IPs), the token is rejected and the user sees the login form.

Solution:

Enable Allow IP address changes during a single session on the Plesk server.

In the Plesk administrator panel:

1. Log in to Plesk as administrator.
2. Go to Tools & Settings.
3. Open Security section.
4. Click Session Idle Time.
5. Enable Allow IP address changes during a single session
6. Leave Session Idle Time at the default 30 minutes unless you have a separate reason to change idle timeout — this value does not block one-time SSO links.
7. Click OK.

Related PanelAlpha settings:

1. The plan privilege Control Panel SSO must be enabled for the service.
2. The hosting server connection (admin URL, username, password) must work — other Plesk operations in PanelAlpha should succeed before troubleshooting SSO.

Learn more in the Plesk Knowledge Base (opens new window).

Issues with Disk Quota Exceeded

Problem: When a client has reached or exceeded their disk space quota, file operations such as creating staging instances, uploading files through the control panel, or other file-related operations may fail silently or with the error Disk quota exceeded.

Solution:

1. Check if the subscription has a disk space limit configured.
2. Verify if there is also a disk quota in place.
3. Ensure both limits are aligned appropriately.
4. Consider increasing the disk quota if it is more restrictive than intended.

Error: The 'wp-config.php' File Already Exists

Problem: During instance installation, the client receives the error:

Error: The 'wp-config.php' file already exists. (exit code 1)

This occurs even though the installation is being performed on a new hosting account. Investigation reveals that a wp-config.php file already exists in the domain directory, but with different database credentials than those PanelAlpha is trying to use.

Cause: WordPress is being installed simultaneously by both PanelAlpha and another source — typically the Plesk WP Toolkit. When the WP Toolkit option is set to Install WordPress in the Service Plan, Plesk automatically installs WordPress when creating a new subscription, which conflicts with PanelAlpha's installation process.

Solution:

1. Log in to your Plesk server.
2. Go to Service Plans → select the relevant hosting plan.
3. Navigate to the Additional Services tab.
4. Change the WP Toolkit setting from Install WordPress to Do not install WordPress or another option that does not auto-install.
5. Click Update & Sync.

This prevents Plesk from automatically installing WordPress, allowing PanelAlpha to handle the installation without conflicts.