---
metadata:
  - name: generator
    content: Diplodoc Platform v5.48.2
alternate:
  - https://yandex.com/support/yandex-360/customers/mail/en/web/problems/certificate-errors.md
keywords:
  - w
  - e
  - b
  - ' '
  - i
  - 'n'
  - t
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---
> **Documentation Index:** Fetch the complete configuration index at https://yandex.com/support/yandex-360/customers/mail/en/llms.txt


# 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”.

<!-- source: en/_includes/web/problems/site-displays-incorrectly/id-site-displays-incorrectly/unsafe-connection-message.md -->
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.
<!-- endsource: en/_includes/web/problems/site-displays-incorrectly/id-site-displays-incorrectly/unsafe-connection-message.md -->


<!-- source: en/_includes/web/problems/site-displays-incorrectly/id-site-displays-incorrectly/certificate-errors.md -->
#|
||
**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](https://yandex.com/support/common/en/support/date-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.
||
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`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](https://en.wikipedia.org/wiki/Man-in-the-middle_attack) attack. Please check your computer for viruses with free anti-virus programs such as [CureIt!](https://free.drweb.com/cureit) from Dr. Web or [Virus Removal Tool](https://support.kaspersky.com/us/viruses/kvrt2015) from “Kaspersky Lab”.
||

|#
<!-- endsource: en/_includes/web/problems/site-displays-incorrectly/id-site-displays-incorrectly/certificate-errors.md -->



{% cut "Disabling HTTPS connection checks in Kaspersky Internet Security" %}


1. Open the antivirus window and click the ![](../../_assets/kis-settings-icon.png) button in the bottom left corner.
1. Go to the **Advanced settings** tab and choose **Network**.
1. In the **Check secure connections** block, choose **Do not check secure connections** and confirm the action.


{% endcut %}

{% cut "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.
1. Go to **Web and email** → **SSL/TLS** and turn off **Enable SSL/TLS protocol filtering**.
1. Go to **Web and email** → **Web access protection** → **Web protocols** → **HTTPS scanner setup** and turn off **Enable HTTPS checking**.
1. Tap **OK** to save your changes.

{% endcut %}


<!-- source: en/_includes/support-button.md -->
<div class="cut-button">

{% cut "Contact support" %}

<div style="padding: 15px;
     margin: 10px 0;
     background: #FFFFFF;
     border-radius: 10px;
     border: 1px solid var(--yc-color-line-generic);">
  <iframe style="background: #FFFFFF;"
        height="700"
        width="100%"
        frameborder="0"
        src="https://forms.yandex.ru/surveys/13644896.d2bd8ce9d37d008ba713202a8126071ffd4f33ba/?lang=en&iframe=1">
  </iframe>
</div>

{% endcut %}

</div>


<!-- endsource: en/_includes/support-button.md -->