If your certificate has issues, you could notice errors on either the Cloudflare application or in your browser. For example, "Failed TLS Intercept Check" on the Cloudflare client or "Certificate Invalid" on your browser.
Try these steps to troubleshoot the issue:
- First, verify that the certificate is correctly trusted on your device. In some cases, the certificate can be installed on your device but not trusted.
- If possible, completely remove/untrust the certificate and reinstall it on your device.
- Completely restart the affected device.
- Re-attempt the same website in an incognito mode window. If you see the block page while incognito, then your web browser has cached an old version of the website.
- Completely clear your browser's cache.
- Switch Filtering Mode to DNS-only.
- Ensure no other VPN or proxy software is installed on your device.
- This device must be your own; if it's managed by your job, the certificate will not work.
- Ensure there are no active Tor connections on your device. This is not common.
It's uncommon, but some devices may not be compatible with the CA certificate, meaning block pages may not be available.
If you have an Android Smartphone...
Most Android smartphones give you the option to install the Cloudflare certificate as either a "VPN or App certificate" or a "CA Root certificate". Make sure you choose the option to install as a CA certificate.
If you have a Windows computer...
It isn't necessary to manually install the Cloudflare certificate. Ensure the setting to install the certificate manually is correctly enabled on the dashboard.