Self assigned IP-problem

Yes, this is your problem.. it won't work without being set to DHCP and NAT.

You will then get a double NAT error but in your case there is nothing you can do about it.

Another problem that can crop up is if the building network is based on 10.x.x.x which is fairly common.. since apple routers also use 10.0.1.x it is important you move the DHCP to 192.168.1.x

On the computer version of the airport utility you do it in network options.

It needs an update - should I do that?

Yes, go ahead and update the AirPort Time Capsule firmware and let the Time Capsule restart.

It says wireless clients: 2 - is that a maximum?

This all depends on whether the Time Capsule is set up as a router.......in which case it will allow up to 50 wireless clients......or whether the Time Capsule is set up in Bridge Mode.......Apple calls this "Off (Bridge Mode).......in which case the number of devices that can connect to the Time Capsule is being controlled by another router that you cannot see.

So, using AirPort Utility on the iOS device, please check the setting for the Router Mode of the Time Capsule as follows:

Open AirPort Utility

Tap on the picture of the Time Capsule

Tap Edit in the upper right corner of the screen

Tap Advanced

Tap DHCP and NAT

Is the Router Mode set to "Off (Bridge Mode)"......in which case the Time Capsule cannot control the number of devices that will be allowed to connect?.......or.......is the current setting for Router Mode set to DHCP and NAT?

I cannot get the MBA on the network, so Ipad/Iphone will be the tool.

OK, thanks for the information.I assume that you have already updated the firmware on the Time Capsule and things are still working OK with the iPhone and iPad.

On the iPad, locate AirPort Utility on the Home screen and tap on it to open the app.

Tap on the picture of the Time Capsule, like you have done before

Tap Edit in the upper right corner of the screen

Tap Advanced

Tap DHCP and NAT

Change the setting from "Off (Bridge Mode)" to DHCP and NAT

Tap Back, Tap Done, Tap Done, etc

The Time Capsule will take a minute to restart. The amber light will be blinking, but do not worry about that for now.

Power off Time Capsule

Wait a minute

Power up the Time Capsule again

Check to make sure that the iPad can connect, then check with other devices to make sure that they can connect

Report on your progress

We'll need to check some settings on the Time Capsule to make sure that it is set up correctly to work with your new wall port Ethernet connection. As it stands, your current connection from the provider likely will not allow all of your devices to connect, because of system limitations.

Do you have AirPort Utility installed on the iPad or iPhone? If not, you can download AirPort Utility from the App Store on either the iPad or the iPhone. It's free.

Post back when you have AirPort Utility installed on your iOS device, and we'll have you check the Internet connection settings.

Turn off your ipad and iphone.. which will free up an IP.

You might also need to power off and on again the TC so it also can start over.

Then the MBA can join the network..

But as Bob says you can do it with iOS version.. just it is poorly laid out.

My IP-adress is 100.xxx and my LAN-IP is 10.x. - is that ok?

This is fine.

If the TC works well with your other devices, then it should work well with the TV.

You are welcome. Glad that things appear to be working well.