Ok. From Mark's link, it seems like the problem may be my old computer etc:
"Devices that received security updates after mid 2015 should have the modern USERTrust RSA Certification Authority root certificate (valid until Jan 2038) in their operating system or browser truststores and should be largely unaffected.
Legacy devices that have not received updates to support newer roots will also likely to be missing other essential security updates and support for standards required by the modern Internet. We strongly encourage decommissioning these devices if their software cannot be upgraded. Non-upgraded, legacy devices should never be exposed to the Internet and special mitigations should be applied to isolate them from neighbor systems."
Messages are the sole opinion of the author, especially the fishy ones.