Today, I got SSL error on Gmail while working with Burp Suite. So, I Googled it and found a very useful way to fix it.
First you need to visit https://pro.portswigger.net/ to get official Port Swigger CA.
Click on More Information > View Certificates and Export the Certificates.
After saving the Certificate from the Port Swigger , Import the Port Swigger CA in the Certificate Manager ( Edit > Preference > Advanced > View Certificates ) and add the certificate to it.
And after installing it visiting Gmail won’t be harder with Burp Suite.
And your certificate is verified.
And here’s a video tutorial which I made :