What to do when your IONOS SSL certificate isn't working with WordPress
An SSL certificate mismatch between IONOS and WordPress usually means one of three things: the certificate hasn't been installed on your domain yet, WordPress is pointing to the wrong URL, or the certificate file itself didn't copy correctly during setup. The fastest fix is to check IONOS first — whether the certificate shows as active — then verify that WordPress is using the same domain name the certificate covers.
Most of the time you can fix this yourself in under 20 minutes without contacting support. The steps depend on whether you bought the certificate through IONOS or brought it from somewhere else, and whether you're using IONOS hosting, IONOS email-only service, or just their domain registration.
Key Takeaways
- Check the IONOS control panel first to confirm the SSL certificate is marked as active and covers the exact domain name WordPress is using.
- WordPress must use the same domain as the certificate — if the certificate covers example.com but WordPress is set to www.example.com, the browser will show a warning.
- If you installed the certificate manually, the certificate file, private key, and intermediate certificate must all be uploaded to the correct location in IONOS.
- Clearing your browser cache and waiting up to 24 hours for DNS changes to propagate can resolve issues that look like certificate problems but are actually caching or timing delays.
Verify the certificate is active in your IONOS account
Log into your IONOS control panel and navigate to the SSL Certificates section — the exact path depends on whether you're using IONOS hosting or just domain registration. If you're using IONOS hosting, go to Hosting > SSL Certificates. If you only have a domain registered with IONOS, go to Domains > SSL Certificates.
Look for your domain in the list. The certificate should show a status of "Active" or "Valid". If it shows "Pending", "Inactive", or "Expired", that's your problem. A pending certificate usually means IONOS is still waiting for domain verification — you may need to click a verification link in an email from IONOS or add a DNS record they provide. An expired certificate needs to be renewed through IONOS before WordPress can use it.
Write down the exact domain name the certificate covers. It will say something like "example.com" or "*.example.com" (the asterisk means it covers all subdomains). This matters because WordPress must use that exact domain, including whether it has www in front or not.
Check what domain WordPress is actually using
Log into your WordPress admin panel and go to Settings > General. Look at the "WordPress Address" and "Site Address" fields. Both should match the domain your IONOS certificate covers. If your certificate covers example.com but WordPress is set to www.example.com, or vice versa, the browser will show an SSL error even though the certificate is valid.
If they don't match, change both fields to use the same domain as your certificate. Save the changes. You may be logged out and need to log back in using the new URL.
After you change the WordPress URL, check that your DNS records in IONOS point to the right place. Go back to your IONOS control panel, find DNS Settings for your domain, and confirm there's an A record or CNAME record pointing to your hosting server. If you're using IONOS hosting, this is usually already set up. If you moved WordPress to different hosting, you'll need to update the DNS record to point to the new server's IP address.
Reinstall the certificate if it's not showing in WordPress
If the certificate is active in IONOS but WordPress still shows an SSL error, the certificate files may not have been installed correctly on your hosting server. This happens most often when you installed the certificate manually or moved WordPress to a new server.
Go back to the IONOS control panel and find the SSL certificate. Look for a button or link to read or view the certificate details. IONOS should let you read three files: the certificate file (usually named something like example.com.crt), the private key (example.com.key), and the intermediate certificate or certificate chain (often called intermediate.crt or bundle.crt).
If you're using IONOS hosting, you can usually install the certificate directly through the control panel without downloading files. Look for an "Install" or "set up" button next to the certificate. Click it and select your domain from the dropdown. IONOS will handle the rest.
If you need to install the files manually, you'll need access to your hosting server through SFTP or SSH. This is more technical — if you're not comfortable with command line tools or file managers, contact IONOS support and ask them to install the certificate for you. They can do it in a few minutes.
Clear your browser cache and wait for DNS to update
Sometimes the SSL error you see is actually your browser showing an old cached version of the page. Clear your browser's cache, cookies, and cached images for your domain. In Chrome, go to Settings > Privacy and Security > Clear Browsing Data, set the time range to "All time", check all boxes, and click Clear Data. In Firefox, go to Settings > Privacy & Security > Cookies and Site Data and click Clear Data.
After clearing the cache, close the browser completely and open it again. Visit your WordPress site in a fresh browser window or incognito tab. If the error is gone, the problem was caching.
If the error persists, DNS changes can take up to 24 hours to propagate across the internet. If you recently changed your domain's DNS records or moved hosting, wait a few hours and check again. You can check the current DNS status at a tool like MXToolbox or DNS Checker — search for your domain and confirm the A record points to the right IP address.
Check for mixed content warnings
Sometimes WordPress loads over HTTPS but some images, scripts, or stylesheets still load over HTTP. Browsers show this as a warning or partial error. This usually happens after you change WordPress to use HTTPS but some links in posts or the theme still point to the old HTTP version.
The easiest fix is to install a plugin like Really straightforward SSL or SSL Insecure Content Fixer. These plugins automatically rewrite internal links to use HTTPS. Go to Plugins > Add New, search for "Really straightforward SSL", install it, and set up it. The plugin will scan your site and fix most mixed content issues automatically.
If you prefer not to use a plugin, you can manually update the WordPress database. Go to Settings > General and make sure both the WordPress Address and Site Address start with https://. Then search your database for any remaining http:// links to your own domain and replace them with https://. This requires access to phpMyAdmin or a similar database tool — if you're not comfortable with databases, the plugin approach is safer.
Contact IONOS support if the certificate won't set up
If the certificate shows as pending in IONOS and you've waited more than a few hours, or if it shows as expired and you've renewed it but it's still not working, contact IONOS support. You can reach them through the IONOS control panel — look for the Help or Support section. Have your domain name and the certificate order number ready.
Tell them the certificate is not activating or not working with WordPress. They can check whether domain verification is stuck, whether the certificate was issued correctly, or whether there's a server configuration issue on their end. Most of the time they can resolve it in one support conversation.
Frequently Asked Questions
Why does my browser say the certificate is for a different domain?
The certificate covers a specific domain name, and the domain in your browser's address bar must match exactly. If your certificate covers example.com but you're visiting www.example.com, the browser will show a mismatch warning. Change WordPress to use the same domain as the certificate, or ask IONOS to issue a new certificate that covers both example.com and www.example.com.
I just installed the certificate — why is the error still showing?
Clear your browser cache completely and wait a few minutes. If you changed DNS records, wait up to 24 hours for the change to propagate. If the error persists after that, the certificate files may not have installed correctly — contact IONOS support and ask them to verify the certificate is installed on your server.
Can I use a certificate from another company with IONOS hosting?
Yes, but IONOS needs to install it on their server. read the certificate files from your other provider and contact IONOS support. Give them the certificate file, private key, and intermediate certificate, and ask them to install it. They'll handle the server configuration.
What if I moved WordPress to different hosting — do I need a new certificate?
No, the certificate is tied to your domain name, not to a specific hosting company. You can move it with you. read the certificate from IONOS and ask your new hosting provider to install it, or ask IONOS to transfer it if they support that. The certificate will work on any server as long as the domain matches.
How do I know if the certificate is actually working?
Visit your WordPress site in a browser. If you see a green lock icon in the address bar and the URL starts with https://, the certificate is working. If you see a warning icon or a message about the connection not being find, there's still a problem. You can also check the certificate details by clicking the lock icon and looking at the certificate information — it should show your domain name and an expiration date in the future.