NET::ERR_CERT_AUTHORITY_INVALID Error in all browser...

 U can find right solution in this url:

https://techglimpse.com/dst-root-ca-x3-expired-certificate-error/

My source is this page and i want backup this right knowledge...

Step 1: Launch Run dialog

Step 2: Type certmgr.msc and hit enter.

Step 3: In the certificate manager window, click on ‘Trusted Root Certification Authorities‘  > Certificates.

Step 4: Lookout for the ‘DST Root CA X3‘ entry and click the delete icon to remove it from the Trusted certification authority store.

Step 5: Download the latest CA certificate from this link.

PS: if u cannot download certificate enter https://letsencrypt.org/certificates/

& download in line ISRG Root X1 "Self-signed: der, pem, txt", red link.... 

Step 6: Double click on the downloaded file and install it. Remember to choose ‘Place all certificates in the following store‘ and choose ‘Trusted Root Certification Authorities'

Step 7: Close the browser and launch it again.

Step 8: Test the website to ensure everything is working fine. If not, you may need to clear the browser cache and try again.

That’s it, this should fix the issue. But can you ask every visitor to your website to do this? Of course not, and this issue may not happen for the visitor who’s using genuine operating systems or a device that receives updates.