It wont let me join a party or play my one friend on xbox live. all my settings are set to OPEN and so are his because i can play all my other friends just not this one.

connect your xbox to internet. click on your account and select"join xbox live" when you register you will be started off with a free trial go to gamestore and buy an xbox live gold membership monthley card or buy a gold member ship online. once your trial runs down you will live off a silver account which doesnt let you join partys, play online with friends,etc.

You are trying to open the NAT on the router for X-box.
For this you will need to reduce the MTU settings on the router to 1365.
You will also need to trigger some ports on the router.
For this you will need to open the router set up page.
Router set up page is the page where you can change the settings of the router

Click Here to know more about router and network

Here's my best idea. Join a party on Xbox LIVE with a friend. This will let you communicate outside of Halo 3. If they can't hear you when you're in the party together, then it's your headset.

To have a friend join a party, go to your friends menu and select a friend. It will then give you the option to invite them into your party. Good luck!

Open or forward ports on the router for your Xbox. Get the ports from Xbox live then configure the router to allow those ports to pass.

Sometimes Non-Opened ports will not allow you to connect with certain other players and there connection. Make sure you open these ports...

• TCP 80
• UDP 88
• UDP 3074
• TCP 3074
• UDP 53
• TCP 53

Send a mail to the wbsite owners. It may be the site has problems.

The case is the way the network is setup are you connecting him via a router? Make sure your NAT is open on the router as well.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edwy_1a56970cf1ea4620

That happened to me once. You should check the wireless device or your ethernet cable( whichever one your using ). If your ethernet cable isnt plugged in on the way it will only let you log into xbox live and that may be it. Lastly try resetting your router and make sure all the wires are plugged in good.
Also Check your NAT settings. If your trying to connect to a friend, You or your friend most probably do not both have an OPEN connection. To find out if you do or dont, go to your xbox's network settings and run a test, if it comes up with a "More Information" button click it, and it will tell you what type of NAT, your xbox is set too. However if it does not come with a More Info button, then your xbox is OPEN.
Make sure both you and your friend do these tests.
If one of you is not OPEN, then you will need to either open some ports up or turn on DHCP and UPnP. But I wont go into detail until you've done the test.
Hope this helps.

your nat type is strict you can change this by opening up your internet explorer go to tools then internet options and make the needed changes

tell your friend to set his party to anyone and not just friends or invite only. its in a settings tab within his party options