The setup requires some kind of handshake between the mobile and the speaker, to identify the latter. When NFC fails are you not offered any other options by the setup procedure? Alternative possibilities are an audio tone between speaker and phone, or even a request to key in a unique PIN code on the speaker’s underside. 

i was only offered the ethernet option when NFC failed. i didnt come across either options that you mentioned, how is this possible?

Ethernet might help things along on the network side, but it’s perfectly possible to setup a new Sonos device using a mobile that doesn’t have NFC at all. Usually the speaker issues a coded audio tone instead. 

It’s been a while since I set up a Beam/g2 but I seem to recall that NFC failed once or twice then, and I was able to complete the task using an alternative method. Is there no text at the bottom of the popup dialog which offers such options?

Can you simply leave NFC disabled on the phone? Or even try with a different phone? 

i tried another phone that has no NFC, no luck. just quits the setup

It sounds like you may need to talk to Sonos Support then. This is mainly a user-to-user board. Sonos staff do monitor it, but often refer users who need 1-to-1 troubleshooting to Support.

One long shot you could try is a factory reset of the Beam: https://support.sonos.com/s/article/1096