Mobile Authenticator Not Sending SMS Code?

[Goop]

My main phone's battery died so i'm using my old phone. I disabled phone guard from pc (and also logged out of all devices) and now i'm trying to enable it on my phone, but when i get to "Step 1 Enter the SMS code we've sent to your phone" i'm simply not getting any messages. Also when i click "Click here to resend it." it just says "Missing or invalid form session key."

Any ideas as to what i can do to fix this?

[Connie]

This thread was quite old before the recent post, so we're locking it to prevent confusion.