I've been playing Ingress for ~2 years. I have 70 portals approved. I play on a new-ish Android phone (oneplus one, cyanogenmod). I've always been able to submit a portal by turning on auto-sync, then, within the game, long-pressing on my scanner, then sliding right to select "create portal".
I'm on version 1.81.0 of the app. I was able to submit as recently as August 26. IIRC, I did get an update to Android 5.1.1 recently, though I'm not sure if that was the point at which I could no longer submit a new portal.
Any suggestions?