I've been trying every day since it came out and still get that error message (10003) this is getting pretty ridiculous I'm 80 hours in and still never got my Ground Zeroes bonuses and I really want to try the FOB stuff but just can't. It's been 13 days now T_T

Same issue here, keep getting error 10003. Is FOB being unlocked at a certain point in the main story or should one just be able to build it whenever online mode is accessible?

That is really odd, I have been able to connect on Xbox One since like day 3 and only have a disconnect once or twice since then.

FOB is unlocked after you finish mission 22, not sure if you have to be connected to build it though.

I have not been able to connect. I tried deleting the game files, and reinstalling, but still unable to connect on Xbox One.

I have the FOB, well I went through the tutorial for it kind of. I'm on Mission 33 at the moment and I just want to be able to play online now.

Are you sure? Because if you did get online you're the first person I have seen in 2 weeks that has been able to across Reddit and Gamefaqs.

If you're still having trouble connecting to the servers try turning of IPV6 in your router. I wasn't able to connect to the servers since launch until after I turned it off.

I have been able to connect online for at least a week. Instead, I've been getting an audio bug every so often.

I have a fix for the 10003 error.

Like you I haven't been able to play online since launch. I'd opened all the ports listed online for MGSTPP (there are more than the default xbox live ones) and that didn't work, also my firewall is pretty open and the network status is Open Nat on xbox one. As a network admin though, I couldn't help but think it was still something on my end since so many other people had little to no problem since the servers have been changed to "Operating normally" on the MGS site. Then one day for no reason I tried connecting my xbox to my mobile hotspot (phone), and lo and behold it worked!

..meaning that although my router/firewall is as open as possible it was still trapping something. I am on AT&T Uverse (using their modem) and I can't stress enough that I opened everything during my testing. However, the modem I'm using (NVG589) doesn't have a DMZ option. It has passthrough options but that's not the same and they didn't work for me.

So what I did; I took a netgear router I had laying around (R6220 AC wireless) and hooked it up to my AT&T modem. Set the AT&T as a straight passthrough (turned off wireless and everything on it) to the netgear. Then set my netgear up as my "real" router (firewall, wireless, etc) and set my Xbox One in it's DMZ (not sure that step was necessary though). And I've had ZERO issues connecting to Metal Gear Servers since. Therefore despite my opening everything I could think of on the AT&T modem and the logs were clear, it was still blocking something without my knowledge/consent.

What's important to note, is that it also means there is a port that the game is trying to use to connect to the online servers that isn't published online. If we knew what that port was we could have added it as an exception in the original AT&T router and not even have to jump through all these hoops. My logs (even on the new router) isn't open enough to tell me those ports, and I could use Wireshark or something to figure it out but haven't yet.

This solution has worked for me and my friends. If it works for you, please help me spread the word. (Now if only we could fix the game stuttering.)

tl;dr AT&T modem blocks something I couldn't stop. So I'm using a different router and set AT&T modem up to pass through to it. I'm fine now.