As the title suggests it won't allow me to connect to an XBL party since the update. I've even tried starting a party and no one can join on me. I've had the person that owns the party send me an invite, it thinks about it for a few seconds, the screen flickers a few times and then I get the same message. I've never had a problem joining any of these people before the update. All of my friends now have the update. Strangely enough, the only person I can join on once I get an invite is the person that downloaded the update on the same day as me. The others were only prompted to d/l the update last night.
Ok, I've done troubleshooting for 3 days now and nothing in the Xbox solutions page works.
I network tested the line - all 3 ticks.
Cleared the storage cache.
Reinstalled my modem/routers latest firmware.
Checked the privacy settings.
Restarted the Xbox after each test.
Unplugged my modem/router for 2 mins.
Hopefully another update will be released to fix these issues as I know I'm not alone.