Hi Jürgen,

Thank you for getting in touch with us. My name is John, and I'm happy to assist you today. I appreciate your patience while we've been working towards your ticket.

I'm sorry to hear that you're having difficulties registering your license key. Issues like this are almost always a web server configuration problem. Please select LayerSlider → Options from your WordPress admin sidebar, then click on the System Status button. If you're using a newer version, you can find System Status here. There should be an entry called "WP Remote functions", which should indicate such an issue. 

Unfortunately, resolving issues like this usually involves contacting the web hosting company since only they have the necessary tools and only they can make the necessary adjustments. Even if System Status doesn't show anything wrong, it's likely a server-side issue, possibly with PHP, that likely requires their involvement.

Although it shouldn't be needed, a manual reinstallation is not a bad idea, considering that you're using a very old and outdated version. You can download the most recent release from your account by signing in with the email address used during checkout. Since you've purchased LayerSlider on Envato/CodeCanyon, you'll need to press the "Import Envato licenses" button once you've signed in.

Your sliders are stored in the database, and you can safely deactivate and delete the plugin, then install the new version as you'd typically do. It will not touch your sliders; they will be available once the latest version is installed.

If the problem persists after the reinstallation, it must be a server configuration issue. Based on my personal experience, web hosting companies aren't too keen to help customers in cases like this, so you might need to press the issue further with them.

Hi Jürgen,

As mentioned earlier, this must be a server configuration issue if the problem persists. System Status was also able to detect this, so there must be something that the web hosting company needs to change. They usually aren't too keen to help customers in cases like this, so I'd recommend pressing the issue further with them. Insisting on looking into the issue again usually does the trick. It's usually the only way since only they have access and the necessary tools to change most server settings. I can offer our services, and if you can provide a temporary WP admin access, we can look around and try to find something concrete, but we won't see the firewall and other relevant settings that only the web host can access to.