Migrating a WordPress site to a new server or domain can be tricky. One common problem users encounter is their WordPress theme not working after migration. While frustrating, this issue is fixable with the right troubleshooting techniques. In this guide, we’ll walk you through the reasons why your theme might not be functioning and how to resolve the issue to get your site back in working order.

Why Does a WordPress Theme Break After Migration?

There are several reasons why your WordPress theme could malfunction after migration:

• Old URLs or paths to media library assets might be broken.
• The wp-config.php file might have incorrect database details.
• The old website and new server configurations might be incompatible.
• Incomplete or corrupt WordPress files might have been transferred.
• Issues with database connection due to incorrect settings can cause a database connection error or error establishing a database connection.

Let’s dive into the most common causes and how to fix them.

Step-by-Step Troubleshooting Guide

1. Check Your Site URL and Permalinks

A common issue during a WordPress migration is incorrect site URLs. When your old domain changes, you need to update the new URLs in the WordPress admin dashboard.

• Navigate to Settings > General in the wp admin and ensure both the Site URL and Home URL are correct.
• Use a search and replace tool like Better Search Replace to update old URLs in the database.

2. Verify Your Database Connection

A broken database connection is often the root cause of many WordPress site issues after migration. You’ll want to check the wp-config.php file to ensure the database details (username, password, host) are correct.

• Open your wp-config.php file and verify the database name, username, and password match your new database.
• If you see an error establishing a database connection, it means these details are incorrect, and you should recheck them.

3. Inspect File and Folder Permissions

If your theme is failing to load, it could be due to incorrect file permissions. The WordPress files and folders need the proper permissions to work correctly.

• Folders should typically have 755 permissions, and files should have 644.
• Use an FTP client or your host’s cPanel to update the permissions and resolve any related issues.

4. Check PHP Version Compatibility

Your WordPress theme might rely on a certain version of PHP to work. If the new server has an outdated PHP version, this could cause your theme to break.

• Check your server’s PHP version and ensure it meets the theme’s requirements.
• You can update the PHP version via your hosting provider’s cPanel.

5. Update Theme Files

Ensure that all your WordPress theme files were transferred during the migration. Sometimes, missing or corrupted files can cause error messages or display issues on your live site.

• Re-upload the theme files via FTP or the admin dashboard to ensure everything is present.
• If the theme still doesn’t work, try switching to a default theme like Twenty Twenty-Three and see if the problem persists.

6. Check for Plugin Conflicts

Sometimes, incompatible plugins can cause your theme to malfunction. To rule out this issue, try deactivating all your plugins from the wp admin dashboard.

• If the theme starts working after deactivating the plugins, reactivate each plugin one by one to find the conflicting one.
• Once identified, you can either update or replace the problematic plugin.

7. Clear Cache and Browser Data

A common oversight after a WordPress migration is not clearing the cache. Cached old site data or old URLs may prevent your WordPress site from loading correctly.

• Clear your browser cache and use a caching plugin like WP Super Cache to clear your site’s cache.
• If you’re using a content delivery network (CDN), clear the CDN cache as well.