Downgraded from 4.4 to 4.3, now Google sync and sign-in fails on device
Alright, this is an interesting one.
So I was on CM 10.2 for the longest time, then I tried CM 11, then finally used SlimKat for a while. Everything was working pretty well on the 4.4 ROMs, except for occasional LTE drops where it just refused to go back to LTE.
Anyway... I decided to go back to a 4.3 ROM. I flashed SlimBean 4.3 first via TWRP. No issues on boot up, LTE works, IMEI intact, WiFi, data, all working. I'm also able to sign in to my Google account - but it only partially works (see screenshot). I also can't sign into any Google services... Play Store, Play Music, Ingress... I just keep getting the "problem communicating with Google servers" error.
Now, I've since tried CM 10.2 again and I've even Odin'ed back to TW 4.3 (MK5). I've fully wiped each time - including full data and sdcard wipe. Every single 4.3 ROM is giving the connection error. I tried going back to a KitKat ROM (CM11) - and it works! No sign in error!
Any ideas what could be causing this?