Kaspersky has a feature to scan your web traffic and when it wants to scan HTTPS connections it needs to intercept and decrypt the traffic, which requires presenting Firefox with a fake certificate. This support article has the steps for setting up Opera by importing a certificate file generated by Kaspersky, and it's most similar for Firefox: http://support.kaspersky.com/us/9093#block1 In Firefox, you would import the .cer file using the Advanced Panel of the Options dialog, here: "3-bar" menu button (or Tools menu) > Options > Advanced > Certificates mini-tab > "View Certificates" button When the Certificate Manager dialog opens, click the Authorities tab (as you would in Opera). Can you get the certificate imported and get to Google?