Hello I hope someone can help me please.
We have 2 Draytek 2860 routers and two adsl lines (different providers) in the same building.
We would like to do the following. Router number 1 port forwards to a webserver and users outside the building. (this is currently working)
We would like router number 2 to pass through http traffic to router number 1 ( external users accessing the same webserver) .
Can anyone help

I'm not sure why you want to do it...why wouldn't the external users just access the first router that the web server sits behind?

That aside, we'd need to know more about the topology. Are these two routers on separate networks, different subnets and/or physically isolated, or all part of the same network etc. ?