This guide covers common problems with importing, uploading, and launching the installer in Duplicator. It offers solutions for resolving import link errors, drag-and-drop upload issues, and installer launch problems related to server permissions and PHP execution.

Note: Duplicator Pro offers two installation methods. Import Installation restores a backup into an existing WordPress site from within its admin area. Classic Installation installs a backup onto a fresh server by running installer.php directly, without an existing WordPress install. Most of the issues below relate to Import; where relevant, we’ve noted when a fallback to Classic Installation applies.

1. Import Link Issues

If your import link is not pulling down the archive file properly, please refer to the table below for supported sources.

Supported and Unsupported Import Sources

2. Import File (Drag-and-Drop) Upload Issues

Common Error Message:

• AJAX ERROR! STATUS:403 Forbidden

Solution 1: Check for Imunify360 or .htaccess Restrictions

If you encounter an “AJAX 403 Forbidden” error, a security layer on your server is likely blocking the upload request. Common causes:

• Imunify360: Many managed hosts run Imunify360, which can flag large or unusual POST/AJAX requests as malicious and block them with a 403. Ask your host to whitelist the Duplicator import request or temporarily disable Imunify360’s web application firewall for testing.
• ModSecurity: A ModSecurity rule (common on shared/cPanel hosts) may be blocking the AJAX request in a similar way. Ask your host to check the ModSecurity audit log for a rule ID tied to the blocked request, and request a targeted exception rather than disabling ModSecurity entirely.
• .htaccess restrictions: Check if a .htaccess file is blocking access.

Contact your host for assistance, or try Solutions 2 and 5.

Solution 2: Upload Archive Manually via FTP

If import via file or link fails, manually upload the archive file:

1. Access your server using an FTP client or cPanel File Manager.
2. Upload the archive (.zip or .daf) to one of these locations:
   • /wp-content/duplicator-backups/imports directory
   • WordPress Root Directory (where wp-config.php is located), this way a Classic Installation has to be performed instead of an Import Installation
3. Go to Duplicator Pro » Import and select the uploaded archive from the list.
   Note, in case you have uploaded the backup to the WordPress root directory, you need to perform a Classic Installation.

3. Installer Launch Issues

Common Error Messages:

• “Duplicator cannot launch Import because on this Server it isn’t possible to execute PHP scripts in folders:”
• cURL error 7: Failed to connect to localhost port 8080: Connection refused

Solution 1: Server Permissions

If you encounter permission errors when launching the installer, review this guide on file permissions.

Solution 2: Verify PHP Execution Is Allowed

Check if PHP execution is blocked in relevant directories:

• .htaccess Block: Look for .htaccess files that may deny PHP execution, such as:
  <Files *.php>
  Order Deny,Allow
  Deny from all
  </Files> 
  The presence of an .htaccess file in wp-content does not necessarily prevent execution. Temporarily rename the .htaccess file to test.
• Security Plugins: Temporarily disable plugins like Wordfence that may block installer access.
• Hosting Restrictions: If PHP execution is blocked at the server level, contact your host or consider switching hosting providers.

If you’re seeing a blank/white installer screen, or 403, 404, 405, or 500 errors when launching the installer, see our dedicated guide: How to Fix a Blank/White Installer or 403/404/405/500 Issues.

Solution 3: Use Alternate Install Modes

If PHP execution cannot be enabled:

1. Manually upload both the installer and archive to the WordPress root directory.
2. Access the installer via https://your-domain.com/installer.php.
3. Choose ‘Overwrite Install Mode’ to overwrite the existing site or database as needed.

Note: Duplicator Pro version 4.5.1+ includes patches that resolve this issue for most setups. Please update to the latest version.

If you’re restoring a backup as part of disaster recovery rather than a standard migration, see our guide on Recovery Points as an alternative to the Import/installer flow covered here.

Solution 4: Docker Containers (cURL Errors)

If running Duplicator in Docker and seeing cURL errors (e.g., connection refused on port 8080), adjust your Apache configuration inside the container:

• Edit /etc/apache2/ports.conf and ensure:Listen 80 Listen 8080
• Edit /etc/apache2/sites-available/000-default.conf to accept connections on both ports.

Refer to Docker and Apache configuration documentation or Stack Overflow for more details.