Troubleshooting WordPress Multisite Domain and Settings Issues

Managing a WordPress Multisite network can be incredibly powerful, but it also introduces a unique set of challenges, particularly when it comes to domain names and settings. A common theme across user reports involves changes not being saved, domains not resolving correctly, or sites redirecting to the wrong address after a migration or domain change.

Why Do These Multisite Domain Problems Happen?

WordPress Multisite is heavily dependent on the site's URL being correctly defined in multiple locations. Unlike a standard WordPress install, a Multisite network stores domain information not only in the database but also in its core configuration file. When these values are out of sync, or when the server isn't configured to recognize the new domain, it leads to a cascade of issues where settings won't stick, domains won't load, and redirects go to the wrong place.

Common Solutions for Multisite Domain and Settings Issues

1. Verify Your wp-config.php Constants

The wp-config.php file is the heart of your Multisite configuration. Incorrect values here are a primary cause of domain-related problems. Ensure the following constants are correctly set for your primary domain:

define('DOMAIN_CURRENT_SITE', 'yourprimarydomain.com');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);

For individual site domain issues, you may also need to define the following for a specific site, though this is less common in Multisite:

define('WP_HOME', 'http://yourproblemdomain.com');
define('WP_SITEURL', 'http://yourproblemdomain.com');

2. Update the Database Directly

If your site was initially set up with an IP address or a temporary domain, the database will be full of old links. Changing the domain in wp-config.php alone is often not enough. You must also update the database.

• Primary Site: The main site's URL is stored in the wp_options table (or wp_1_options in large networks) under the siteurl and home options.
• Subsites: Each subsite has its own wp_#_options table where its siteurl and home values are stored.
• Domain Mapping: If you are using a domain mapping plugin or the built-in Multisite domain change feature, also check the wp_blogs and wp_site tables.

Warning: Always back up your database completely before running any search and replace operations. Use a reliable tool like the CLI-based Search Replace DB script or a trusted plugin like Better Search Replace to safely change all instances of the old URL to the new one.

3. Check Your Server and DNS Configuration

WordPress can only respond to requests that your web server passes to it. A very common point of failure, especially after a host change (like moving to DirectAdmin), is the server's virtual host configuration.

• Wildcard Subdomains: For subdomain networks, ensure a wildcard DNS record (e.g., *.yourdomain.com) points to your server's IP and that your web server (Apache, Nginx, OpenLiteSpeed) is configured to accept requests for all subdomains.
• Server Aliases: The server's virtual host file must include the new domain name in its ServerAlias directive to recognize and serve traffic for it.
• DNS Propagation: After changing DNS records, allow up to 48 hours for the changes to propagate globally. You can use tools like WhatsMyDNS to check propagation status.

4. Clear All Caches

Caching can often make it seem like changes haven't been applied. After making any configuration or database changes, clear the following:

• Your WordPress object cache (if using Memcached, Redis, etc.)
• Any page caching plugins (e.g., W3 Total Cache, WP Super Cache)
• Your browser cache
• Your CDN cache (e.g., Cloudflare)
• Your server-level cache (e.g., OpenLiteSpeed LiteSpeed Cache)

Conclusion

Resolving domain and settings issues in WordPress Multisite is typically a process of elimination. Start by verifying your core configuration in wp-config.php, then move on to a thorough database search-and-replace, and finally, double-check your server and DNS settings. By methodically working through these areas, you can usually pinpoint and fix the problem, getting your network and its sites back online correctly.