This could include a setting on their computer, antivirus software, or the internet connection. There are a few main reasons you may see this error: While the NET::ERR_CERT_DATE_INVALID error is not unusual and can be easily fixed, it can sometimes indicate a legitimate threat. You can ignore it and click through to the page you’re trying to visit, but we don’t recommend it.
In most cases, the error won’t actually prevent you from accessing the site. The NET::ERR_CERT_DATE_INVALID error message in Firefox.
