Issues with certificates appear frequently across various sites.
Issues with certificates appear frequently across various sites.
Hello everyone, on my Windows 10 Pro machine I've noticed several websites displaying an invalid certificate issue. Even well-known sites like cnet.com are affected. They display messages such as "Your connection isn't private" and when I try to proceed, the certificate verification fails. Some pages block me from clicking 'Proceed' entirely, showing no alternative options. Instead they state something about HSTS and temporary network problems. This issue appears across all browsers. I suspect it might be related to my dad's work applications. He relies on a VPN for remote access and this interferes with the settings. The problem was resolved on his Surface Pro after a full Windows reset, but that option isn't available for me due to sensitive data. I attempted a clean install of Windows with "keep apps and files" selected, but it didn't work. I double-checked my time settings as well. For the sites where I can still click 'Proceed', the certificate comes from R3. However, some listings don't mention R3 at all. The software he used included Big IP F5 and Citrix Receiver.
There are a few potential explanations I’m considering. First, the certificates might be faulty, which can happen sometimes when a system administrator makes a mistake. Second, they might only show bad certificates, possibly because your device isn’t interpreting them correctly—this would imply all sites have issues, which seems unlikely. The timing and context could relate to the operating system or software being used, affecting how certificates are displayed. I’m still trying to figure out why this is happening. I noticed similar problems with Mozilla at one point, but after updating my OS it resolved. A quick refresh might help if you’re on Windows. Let me know if this makes sense.
The organisation seems to be just R3. Is there a clear expiry date for the certificate? It looks quite questionable overall. Do you notice any issues with certificates when you disconnect from the VPN? If not, it might just be a firewall issue during the VPN connection; otherwise, it shouldn't happen. I’d suggest reaching out to his work or asking your dad to verify the certificate details directly with their support team. If there’s a mismatch, report it as a security concern. It could be paranoid, but cyber threats are increasingly frequent. To be safe, reset passwords for your most important accounts from another device until this error is resolved.
If the certificate hasn't expired but still causes issues, it suggests the authority isn't trusted. This is suspicious, similar to a man-in-the-middle attack—usually companies install such certificates on devices without proper verification. It’s risky, especially if you don’t see third-party certificates on your machine. Since you use multiple VPNs and remote desktops at work, it’s unusual for any unauthorized certificate to be installed. Make sure your dad contacts his company’s IT department to confirm the situation is normal.
R3 acts as a LetsEncrypt intermediate and sometimes not all systems accept the full letsencrypt chain. I’d begin by bringing in the library. Also, internal PKI setups can interfere with certificates—check proxy configurations for HTTP interception.