I get security certificate errors

When a security certificate error occurs, you get the message:

  • “Your connection is not private”.
  • “This site threatens your computer security.”
  • “Incorrect certificate”.
  • “Error in security certificate”.
  • “This is an untrusted connection”.

Untrusted connection or invalid security certificate errors may occur due to a conflict between the browser and computer settings. These errors may also be caused by your antivirus software. To find out why you are receiving the certificate error, look for its code at the end of the message.

Error code

Solution

ssl_error_bad_cert_domain

Make sure that you've entered the correct address in the browser's address bar: mail.yandex.com or passport.yandex.com, with com followed by / instead of a dot or another character.

err_cert_date_invalid
sec_error_oscp_invalid_signing_cert
sec_error_expired_issuer_certificate
sec_error_expired_certificate
sec_error_ocsp_future_response

Make sure that your date and time are correctly set on your computer. If the wrong date or time is set, the system may incorrectly determine that the certificate period didn't start yet or that it is already expired.

err_cert_common_name_invalid
err_cert_authority_invalid
sec_error_unknown_issuer

Make sure that your antivirus settings are not configured to check HTTPS connections. More information about how this can be done in Kaspersky Internet Security and ESET NOD32 Smart Security can be found under the table.
If you don't have an antivirus program on your computer, hackers may replace your security certificate using malware or an MITM attack. Please check your computer for viruses with free anti-virus programs such as CureIt! from Dr. Web or Virus Removal Tool from “Kaspersky Lab”.
Disabling HTTPS connection checks in Kaspersky Internet Security
  1. Open the antivirus window and click the button in the bottom left corner.
  2. Go to the Advanced settings tab and choose Network.
  3. In the Check secure connections block, choose Do not check secure connections and confirm the action.
Disabling verifications of HTTPS connections in ESET NOD32 Smart Security
  1. Open the antivirus window, go to the Settings tab and click the Additional link.
  2. Go to Web and email → SSL/TLS and turn off Enable SSL/TLS protocol filtering.
  3. Go to Web and email → Web access protection → Web protocols → HTTPS scanner setup and turn off Enable HTTPS checking.
  4. Tap OK to save your changes.
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