I am struggling to get a connection from my Airport Express. Essentially my light on my airport express is green. My network is set up and Airport Utility says it's good. Modem connects to comp via ethernet and gets signal. What might be my problem?

If the computer is plugged into the modem or using the modem wireless.. it will not find the express.. this is an issue in Mac OS.. particularly Yosemite.. a classic network dog. Ensure the computer is plugged directly into the Express.. and the express plugged into the modem.. or use wireless on the computer.. to the express.. not the Xfinity modem.

Xfinity has no solution but to contact apple support

If you have an Xfinity modem/router and it is providing your Internet connection....

Modem connects to comp via Ethernet

and your MacBook Pro is connected to the Xfinity device using a wired Ethernet cable connection.....

What is it that you want the AirPort Express to do on your network? What service will it provide?

How will the AirPort Express connect to your network? Wired Ethernet connection to the modem/router? Wireless connection to the modem/router?

OK, thanks for the information. This does help clarify things.

The Motorola Surfboard modem......would you be able to look on the back or bottom of this device to get the model number? (We don't need a serial number, so please don't post personal information like that).

We ask since Motorola makes dozens of "modems", and some of them include routers and some do not. The actual type of "modem" that you have will determine the correct set up of the AirPort Express.

Finally, in order to provide the correct set up steps, we would need to know what operating system you have installed on the MacBook Pro. If you are not sure about this, click the Apple icon at the upper left of the Mac's screen, then click About This Mac and post back with the OS X version number that you see there.

So, to summarize, we would ask for a bit more information to better understand things and provide a solution:

1) The model number of the Motorola modem

2) The operating system that your Mac is using

With that information, we will be able to provide the correct setup steps to get the AirPort Express working the way that you want.

OK, thanks.

Unfortunately, the Motorola SB6121 and Apple routers sometimes do not get along all that well together. The same is true for another popular model, the Motorola SB6141.

Motorola and Apple both make good products, but for a number of users.....including me.....they just don't work very well together. We'll try our best, but if you continue to have difficulty, you will need to make a decision on whether to keep your modem or your AirPort router.

To start, power off the SB6121 completely. That would mean pulling the power cord from the back of the modem, or pulling the AC power supply from the wall socket.

Leave the modem powered off for at least 30 minutes. That might be a much longer time than you have heard that it takes for a modem to reset, but in this case, we want the equipment back at the cable company to fully reset as well, and that usually takes at least 15-20 minutes. Please stick with at least 30 minutes for the modem power down. Longer will not hurt at all. Disconnect the Ethernet cable from the modem as well as the co-ax cable.

While the modem is powered down, power up the AirPort Express....if it is not already powered on....and let it run a few minutes. Then, hold in the reset button on the back of the Express for 7-8 seconds and release. Allow a full minute for the AirPort Express to restart to a slow, blinking amber light status. Then, power it off.

After the 30 minute modem power down, connect the co-ax cable to the modem and connect the Ethernet cable from the modem to the WAN "O" port on the AirPort Express.

Power up the modem and let it run for at least 10 minutes by itself.

Then, power up the AirPort Express and let it run a few minutes.

Try the setup again on the AirPort Express and try things out. Please report on your results.