The ERR_SSL_PROTOCOL_ERROR error message means that your browser cannot make a secure connection to a website. This usually happens when there is something wrong with the site's SSL certificate, but it can also be due to something going wrong on your own device.
Possible causes
- Website SSL configuration problems: For example, an expired certificate or a wrong setting on the server.
- Wrong date and time on your device: If your computer clock is off, that can cause SSL certificates to expire.
- Outdated or corrupted browser data: Old cookies or cache may cause conflicts.
- Browser settings or extensions that conflict: Some settings or extensions may block the secure connection.
How to resolve the ERR_SSL_PROTOCOL_ERROR?
So the problem can be caused on your own laptop or mobile, but it can also originate on the server where the website resides. Below are some settings you can check or solutions you can apply:
Check your website's SSL settings
If you run a website, it is important to check that the SSL certificate is correctly installed and valid. An SSL certificate ensures that communication between the user's browser and your website is encrypted and secure. Problems with this certificate can lead to the ERR_SSL_PROTOCOL_ERROR.
1. Use a reliable SSL testing tool
To check whether your SSL certificate is set up properly, you can use an online SSL testing tool. We recommend Qualys SSL Labs tool to use. This allows you to easily check if there are any problems with your certificate. Go to the SSL Labs website, enter your domain name and click 'Submit'. After the scan, you will see a report with the results of the SSL certificate checks.
2. Check the validity of the certificate
In the SSL test tool report, you can check the following things, among others:
Certificate status: Is the certificate valid or expired?
Certificate chain: Are all intermediate certificates installed correctly?
Supported protocols: Does your server support modern and secure protocols such as TLS 1.2 or 1.3?
A good score in these areas indicates that your SSL certificate has been installed correctly and is not causing any problems.
3. Check the server settings
Sometimes server settings can also affect the SSL connection. Make sure your server is configured to support secure protocols and cipher suites. You can often check this through your hosting provider's control panel or by contacting their customer support.
4. Consider a reinstallation or replacement
If you still experience problems after performing the above steps, consider reinstalling or replacing the SSL certificate. This may help if something went wrong during the initial installation or if the certificate became corrupted.
settings on your device that may be causing the problem
Below is the solution you can go through to find out if the problem is occurring on your own device.
Check the date and time on your device
A wrong date or time on your computer or mobile can cause a surprising number of problems with SSL certificates. This is because SSL certificates are time-sensitive: they are only valid within a certain time window. If your device has the wrong date or time, the browser may think the certificate has expired, when in reality it hasn't.
Therefore, always check that your device has the correct date and time first. The easiest way is to set your device to automatically synchronise the time with an Internet server. That way, you don't have to pay attention to it yourself, and you avoid this simple error blocking your connections.
Tip: also don't forget to set the time zone correctly, as a wrong time zone can cause the same problem.
Clear your browser data
Sometimes your browser blocks a secure connection because old files in the cache or outdated cookies cause conflicts. This happens, for example, if a website has recently been updated, but your browser still uses old data.
To fix this, go to your browser settings and look for options such as "Delete browsing data", "Empty cache" or "Delete cookies". Clear both the cache and cookies for the site you are having problems with, or for all sites if you want to be sure.
After clearing this data, restart the browser. In many cases, the
ERR_SSL_PROTOCOL_ERRORbecause of this immediately, as the browser now makes a fresh, up-to-date connection to the website.
Disable the QUIC protocol
QUIC is an experimental network protocol used by Google Chrome to make websites load faster. In some cases, however, this protocol can cause conflicts with SSL certificates and thus cause the
ERR_SSL_PROTOCOL_ERRORtrigger.To fix this, open Chrome and type in the address bar:
chrome://flags/#enable-quic. Press Enter and you will see the option "Experimental QUIC protocol". Set this option to Off (Disabled).Then close the browser completely and restart it. Now Chrome no longer uses QUIC and is more likely to connect to the website again without any problems.
Tip: this is a safe change and can always be reset if you want.
Temporarily disable your antivirus or firewall
Sometimes security programmes such as antivirus software or a firewall can block your browser's SSL connection. This can lead to the
ERR_SSL_PROTOCOL_ERROR, even when everything else seems to be fine.To test if this is the cause, you can temporarily disable your antivirus or firewall and try reloading the website. Important: only do this on websites you are sure are safe, because while switching off your device is less protected.
If the website now does load, you know that your security programme is causing the problem. Often, you can then add an exception in the settings for that specific site, so that your security remains active, but the connection is problem-free.
What if the problem remains?
If you still get the error message after these steps, the problem may lie deeper, for example in the website's server settings. In that case, it is advisable to contact the hosting provider or a web developer.
