Fibre installation with Apple Airport Express (Gen 1)

[#1]

Hi! I'm a new PlusNet fibre customer and the BT engineer came today to install it. Unfortunately, my Plusnet router got lost in the post, so I was unable to get it set up.
The BT engineer installed the OpenNet modem and I tried using my own wireless router (Apple AirPort Express Gen 1)  to get connected to the internet. However, it didn't work, with my apple network diagnostics showing green for Airport, Airport Settings, Network Settings, ISP but red for Internet and Server. I tried to use Airport Utility and changing Internet connection to PPPoE, plus inputting my username@plusdsl.net and my password, but no luck.
When i tried to connect my computer directly using the ethernet cable, using PPPoE, similarly inputting my username@plusdsl.net and my password, it did work and i was able to connect to the internet.
Does anyone have a similar problem? If so, can anyone advise as to how to make it work using my Airport Express? Should i be using DHCP instead?
Thanks v much!

[#2]

welcome to the forums
that should work, have you tried doing a factory reset before setting up the pppoe connection? that sometimes helps.

[#3]

Yup, i tried to do that, but somehow it didn't work.
I'm not sure if it's something i did wrong, as my previous network settings on the airport express were still valid (i.e. network name, and WPA2 password) which indicates that it didn't reset?
Whenever, i key in my PPPoE details, it just doesn't go anywhere.

[#4]

you haven't done a factory reset if it still has your WIFI settings.

[#5]

thanks, that makes sense. I shall try again when i get home. Keeping my fingers crossed!

[#6]

you need to use the button near the audio port

[#7]

I tried again and failed miserably. I pushed the reset button again, however, am still having the same issues. Are there any other options I have to get it to work?
Thank you!

[#8]

Did you do a Factory Default reset?  http://support.apple.com/en-gb/HT3728