Contacting Server, NAT Strict intermittent issue

Need help. This problem hasn’t gone away since early in the year 2020 near the release of Halo 2 on PC, or soon after.

9 out of 10 times I load up Halo:MCC on PC I get “Contacting server” issues not allowing me to join multiplayer games. I can check the Xbox companion application and it says I have a NAT type:Strict. Well okay, but that doesn’t make sense when I can go right over to Call of Duty:Warzone and it informs me that I have a NAT type:OPEN and I have no problems joining a game, using a headset/mic etc…

I’ve tried messing with my router, removing my router completely and plugging the modem in straight to my PC, signing in and out on Halo:MCC, signing in and out on the Xbox Game bar app and nothing fixes this issue to get me online–but what gives? Only once in a while can I seem to get through after waiting a while. I’ve seen the Xbox “fix” link on this, but it’s really not the issue in my opinion since ONLY Halo:MCC is giving me this issue. Every other online multiplayer game works fine.

Please help.

I’m on Windows 10, not sure what other information would help.

No one has this issue? Still having to this date.

Month later. Still getting the same problem intermittently. I even went through a reddit forum that had a final fix for at least the Xbox app on Win10 to recognize my NAT as open and connected without issue. But then Halo:MCC on PC (thru Steam) still gives problems connecting. Sometimes I can play a little campaign and it’ll connect up, sometimes I can load up MCC and jump right into multiplayer without any issue… and then nights like tonight I start it up, log in, play some offline firefight, wait another 20 minutes during dinner and come back and it still gives me the message “Contacting Servers.”