Hi angp, Sorry you are having problems. Obviously all those sits will not be wrong. The most likely reason is probably that you have security sofware not set up properly to work with Firefox.

Please have a look at

• What do the security warning codes mean?
• How to troubleshoot security error codes on secure websites

Please list all the security related software you use with maker, name and full version details.

Both firefox and thunderbird can't go to mozilla.org as the it say: What does "Your connection is not secure" mean? How to troubleshoot the error code "SEC_ERROR_UNKNOWN_ISSUER" on secure websites

checked the info, but still no help

Your connection is not secure

The owner of www.mozilla.org has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

Learn more…

Report errors like this to help Mozilla identify and block malicious sites

Hi nicholas2, Please post your own question using /questions/new

When you post please try to follow the prompts to provide full system information etc

In the main part of your question please link all the security related software you use with company name, software name and full version number.

Once you have posted a new question please reply briefly here just to confirm you have done that, and we will be able t find your post.