TL;DR: If you get an error about NET:ERR_CERT_DATE_INVALID that make your tablet stop working, try to set manually DATE and TIME (both) to current one of your timezone.
I was trying to fix my step-parents tablet (old Samsung one, SM-T2.0NU, Android 5.0.2) that stopped working suddenly I was told while on YouTube.
Problems noticed, actions taken, etc. (you can skip to solution):
- I had NET:ERR_CERT_DATE_INVALID error in Chrome. Noticed that some website worked (non-https ones and some others it seems).
Most of the things was not working, like accessing Play Store. Without any meaningful error message, just an option to "retry".
- I thought it was the internet, etc. So I rebooted router, tablet, removed everything Wifi, disconnect/reconnect, tried to set internet to manually (but it did have an IP automatically), etc.
- Cleared Chrome history, cache, etc.
- Automatic date and time option was not showing, but I could see the option by using the search, but when I tried to tick it, it bring me to date and time and was not applying any solution.
- I tried multiple time to put the time myself...
- Only after an hour trying to apply gazillion of solutions did I try to put the date in the past to notice the date was already 3 months behind (why? no clue). Then I set it to today's date and everything started working again.
I don't know if this will trigger the automatic management of date and time (I still cannot check the box even through search in settings), but I might not be the only one falling here to try to fix that issue that was preventing us using the tablet normally (I believe security settings verified that date and time were correct and I saw a lot of people having the same issues without a fix).