'Cannot establish network' error on both my android devices, cannot link accounts or topic

'Cannot establish network' error on both my android devices, cannot link accounts or anything on the devices. Tried deleting cache as well as factory reset. Please help!

I have 2 Android devices, an HP Slate7 Voicetab and an older Motorola. The tab is rooted but the phone is not.

I exchanged sim card from the phone to the tab for a while and then changed back. A little while later my tab started showing the error 'Google play services crashed'. And when I went to Google play store to download any app, it constantly showed me no internet conection despite being connected to WiFi. Other things worked fine except Google Hangouts.

And when I put the sim card in the phone again, it is now showing me the same exact error. I cannot access Opera, Google Play, Messenger, or most apps that use internet except the stock browser which keeps showing me 'security warning: There are problems with the security certificate for this site' error for EVERY site.

I factory reset my tab and now I can't even log into my Google account.

Is there ANYTHING I can do to fix this? This is infuriating