Every device on my network is showing NET::ERR_CERT_AUTHORITY_INVALID when I try to use services such as YouTube and Netflix. It seems more likely to be related to the router or modem than to an individual device. Google searches sometimes work, but clicking the results triggers the certificate error. I have already rebooted and reset both the router and modem. What could be causing this, and how can I fix it?
4 Answers
This can happen if the router is redirecting traffic to an internal page, such as an internet outage notice, payment reminder, or setup page, that uses a self-signed certificate. Contact your internet provider to check whether the account or connection is being redirected.
You can inspect the certificate details in the browser and see whether the certificate name matches the website, whether the validity dates include the current date, and which organization issued it. If every device and browser has the same problem, that points away from extensions or device security software and toward the router, ISP, or network time settings.
Check the date and time on the router and affected devices. HTTPS certificates are only valid within specific time ranges, so an incorrect router clock can make legitimate websites appear untrusted. If the router supports it, verify that automatic time synchronization or NTP is enabled.
I wasn’t sure where to check the time at first, but logging into the router and correcting its settings seems to have fixed the problem.
A full reboot is worth trying, but since you already reset the equipment, the next steps are checking the router’s clock, confirming the WAN connection is active, and looking for an ISP redirect or captive-portal page. Certificate errors across unrelated devices usually indicate something shared by the network rather than a problem on each individual device.
It turned out not to be security software. After logging into the router and adjusting its settings, the issue went away.