While this may not be a common issue, this has happened to a friend’s computer, so I am sharing this anyway.

If your computer’s web browser is giving you an invalid certificate error on trustworthy websites, check your computer’s clock (the time, date, and year). If your computer’s clock is wrong, you may see these errors while browsing. Update the clock to the correct time and date and if this was the cause of the issue it should be fixed now.

 

Note: the clock is not the only cause for certificate errors, sometimes they are simply due to a misconfigured web server (nothing YOU can fix).

Just thought I’d share the tip.

-Matthew