Why do I get a Security Certificate warning in my Browser?
This error occurs when the website you are visiting (or when an app you are using tries to access a web server) discovers that your tablet's credentials do not match theirs.
In most cases, this usually means your tablet’s time and date settings are wrong. To confirm or adjust these settings, go to Settings > Date & Time > and tap the option labeled Automatic to make sure the green check mark is removed. Then make sure the Date, Time, and Time Zone are all correct.
If you receive that error message again after these steps, just press the Continue option. After this, you should no longer see these warnings. If so, you may also need to reset your Browser to defaults (within the Browser, select Menu > More > Settings > Reset to default).