ERR_CERT_COMMON_NAME_INVALID is a very popular SSL error during website loading. In most cases, the problem is caused by incorrect configuration of the certificate on a server. However, it may appear due to antivirus and firewall or other third-party software and extensions. Check the error example in the screenshot below.
Fixing the NET:: ERR_CERT_COMMON_NAME_INVALID error is not very difficult, but would take some time and additional steps. You must first identify the cause of the mismatch error.
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Solution 1: Check date and time are proper
Your Chrome browser will display ERR_CERT_COMMON_NAME_INVALID error in case the date and time are wrong on your computer or mobile device. Recheck and adjust it in your PC settings.
Solution 2: Check browser extensions
In some cases, the problematic browser extension could be a reason for the error. First of all, try to open the website in the Incognito window, and if that solves the issue then no need to check extensions. Otherwise, follow the next steps:
Click the "three dots" button on the top right corner of your browser window
Select More tools and Extensions
Turn off extensions one by one to find culprit extension and delete it to fix the browser error.
Solution 3: Check Installed SSL certificate
In some cases, the problematic browser extension could be a reason for the error. First of all try to open the website in the incognito window and if that solves the problem then you don't need to check the extensions. Otherwise, follow the next steps:
Click the "three dots" button in the upper right corner of your browser window
Select more tools and extensions
Deactivate the extensions one by one to find the culprit extension and remove it to fix the browser error.
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Solution 4: Protection of both with/without WWW
All the single-domain SSL certificates we sell protect the WWW and non-WWW versions of your domain name. However, there are some certificates that do not protect them by default. In that case, you may have a problem using redirect from WWW to non-WWW or opposite option.
The possible solution is to install a suitable SSL certificate or remove any redirects and install Multi-Domain or Wildcard SSL or even single domain SSL to protect all the domains/subdomains in use.
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A very popular problem is forgetting to buy an SSL certificate. WordPress owners enable the secure HTTPS protocol for their website without installing or buying SSL as they get NET:: ERR_CERT_COMMON_NAME_INVALID error message in the browser. There are two possible solutions in that case.
buy an SSL certificate and install it on your web server;
or change HTTPS to HTTP to enable your website without any protection and encryption of the transmitted data.
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Solution 6: Clear the SSL cache
The browser's SSL cache may be a problem. You should try to clear the cache to resolve the error.
For IE / Edge. You must open the Internet properties and look for the "Content" tab, there will be a button to "Clear SSL status".
For the Chrome browser, the process is similar, click the "Three Dots" button at the top right of the browser, look for "Settings". There you will find "Advanced Settings" at the bottom of a page. Now search for "Open proxy settings" and you will see the "Content" tab with "Clear SSL status"
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Solution 7: Proxy settings
You may have limited browsing experience if automatic configuration detection is not set using proxy settings. The solution is to right-click on the network access icon to view Internet properties. Touch the "Connection" tab and then "LAN Settings".
You will see a new window where you will need to click to check the box next to "Automatically detect settings" if it is not already checked. Once this is done, you can try to open the website again to see if the error was fixed.
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Solution 8: Update OS and Browser
The classic idea is to make sure that your operating system and browser are up to date, as old or outdated software can bring unexpected problems. The developers are working hard to create new patches and bug fixes, so having an updated system is essential.
Solution 9: Checking your Firewall/Antivirus
We suggest checking Firewall and Antivirus settings and LOG files to make sure they are not blocking the website you are trying to visit. Check the reason for the block carefully, if you found a block, as they are probably trying to protect you from a malicious website. We do not suggest disabling the antivirus.
Conclusions to summarize
You can clearly see that there are several possible problems that can lead to FIX ERR_CERT_COMMON_NAME_INVALID error. However, it is a known bug and there are fairly simple steps to fix the problem. Check your PC's data / time, browser extensions, try to clear SSL cache, recheck Proxy settings and update OS with browser to latest versions. That should definitely help. Good luck!