Every device on my home network started showing NET::ERR_CERT_AUTHORITY_INVALID when opening sites and using services such as YouTube and Netflix. It seems unlikely to be a problem with each individual device, so I suspect the router or modem. Google searches sometimes work, but clicking through to other pages triggers the certificate error. What could cause this across the entire network, and how can I fix it?
3 Answers
This can happen if the router is redirecting traffic to an ISP or login page with a self-signed certificate. Check whether your internet service has an account or outage notice, and contact the ISP if necessary. Restarting the modem and router is also worth trying, although it may not fix an account or redirect issue.
If the problem continues, inspect the certificate details in the browser. The certificate name should match the website, the validity dates should include the current date, and the issuer should be a legitimate certificate authority. Test another browser and temporarily rule out shared security software or extensions. If the certificate points to the router, ISP, or an unexpected security product instead of the site, traffic is probably being intercepted or redirected.
Check the date and time configured on the router and on the affected devices. HTTPS certificates are only valid within specific time ranges, so an incorrect router clock or a failed time-sync service can make perfectly legitimate sites appear invalid. Logging into the router and correcting its time settings resolved the issue in this case.
I checked the router settings and logging in seemed to clear up the problem along with the other steps I had already tried.