Zyxel router access after factory reset

[hardwareuser52]

Hi, I have a Zyxel router P-2812HNU-F1 which won't allow admin access after a factory reset.
I am sure it is not bricked as the LEDs flash and stay on after power up, ethernet ports LED shown correctly, wifi connects to laptop, DSL LED comes on after a minute, but the internet LED stays red (no internet connection.) I can connect using ethernet to the router's admin setup page.

I have tried power cycle, factory reset several times, and the LEDs respond to this reset by changing colour, flashing then staying on.

I used 192.168.1.1 to connect to the admin set up page and am prompted to enter a user name and password, which should be "admin" and "1234" by default and also after a factory reset.
All I get is a red error message, "wrong user name or password."
Why doesn't a reset allow me to access the router, could it be blocked in any way?

Can anyone help please?
Thanks. I am tearing out what is left of my hair!

 

[jsmithepa]

Try both admin and administrator.
Try blank password as well as password.

If that doesn't work, contact Xytel support with your firmware version.

 

[hardwareuser52]

Try both admin and administrator.
Try blank password as well as password.

If that doesn't work, contact Xytel support with your firmware version.

 

[hardwareuser52]

Hello, thanks for the ideas. I tried the user name and password options, but still get the error message that they are incorrect, also tried another factory reset as well, no change.
I have contacted Zyxel support, who sent me a link to the manual which I have already read, and they also suggested doing a reset, and trying admin and 1234.
It seems I am stuck with a "working" router, or one very close to it, but it won't reset to default settings.
Maybe the firmware needs upgrading, but without an internet connection not sure how that can be done.
Can a router be locked down or blocked by ISP to prevent a reset?

 

[jsmithepa]

Oh, if this is an ISP supplied piece of equipment then the ISP maybe running their own firmware, and their own factory login identity.

 

[hardwareuser52]

Oh, if this is an ISP supplied piece of equipment then the ISP maybe running their own firmware, and their own factory login identity.

 

[hardwareuser52]

Yes, it could be but as I bought it second hand I don't know its origin. It came boxed with all leads, manual, setup CD and looked almost new. It may have been sent as part of an ISP package, but I don't know who supplied these routers about 3-4 years ago I guess. The plug is standard UK and has a recent safety sticker expiring in December 2016.
I like the idea of a firmware upgrade, but not sure how to do this. There is an upgrade listed on the Zyxel site, but to use it I need admin access to the router, then once in can check firmware upgrade options and upload it from my computer.

 

[jsmithepa]

Well not knowing its origin can be a problem, I assume you already looked around and found no identifying label? A quick Google shows this is a OpenWrt capable box so who the neck knows what the old owner did with it. Maybe the end of the tunnel for you and no light.