How to Fix an SSL Certificate Issue Between IONOS and WordPress

SSL certificate errors between IONOS and WordPress are among the most common — and most frustrating — problems site owners encounter. The good news: most of them follow predictable patterns, and understanding what's actually happening makes them much easier to resolve.

What an SSL Certificate Actually Does

An SSL (Secure Sockets Layer) certificate encrypts data traveling between your visitor's browser and your web server. When it's working correctly, your site loads over https:// and browsers show a padlock icon. When something breaks that chain of trust, visitors see warnings like "Your connection is not private" or "ERR_SSL_PROTOCOL_ERROR" — and WordPress itself can behave erratically.

IONOS (formerly 1&1) manages SSL certificates at the hosting level, while WordPress manages URLs and content delivery at the application level. Problems often arise in the gap between those two layers.

Common SSL Issues Between IONOS and WordPress

1. Certificate Issued but Site Still Loads Over HTTP

IONOS may have activated an SSL certificate in the control panel, but WordPress doesn't automatically know to use it. If your WordPress Address (URL) and Site Address (URL) in Settings → General still say http://, your site won't use the certificate even though it exists.

Fix: Update both URLs from http:// to https:// in WordPress settings. If you're locked out, you can edit wp-config.php directly or update the values in your database via phpMyAdmin.

2. Mixed Content Warnings 🔒

Mixed content happens when your page loads over HTTPS but some assets — images, scripts, stylesheets — are still referenced with http:// links. Browsers flag this as insecure even when a valid certificate exists.

Fix: Use a plugin like Really Simple SSL or Better Search Replace to scan and update hardcoded HTTP references in your database. IONOS's own SSL activation sometimes triggers a redirect but doesn't rewrite embedded content URLs.

3. Redirect Loops After Enabling SSL

This is a known complication with certain IONOS hosting configurations. When IONOS handles SSL termination at the server or proxy level, WordPress may not detect HTTPS correctly. It then keeps redirecting, creating an infinite loop.