XBOX One NAT Type set to Strict randomly one day - and I can't change it back

I play over wireless on a Verizon FIOS router with great internet speed and I've never had problems. My roommate also has an Xbox one and is connected via Ethernet. I opened up my ports to Xbox a few months ago (changed NAT from moderate to open), and
yesterday when I turned my Xbox on my NAT was strict. I can join partied, but it just shows an "X" next to my name and boots me out with a party error shortly after. Tried playing Destiny but I couldn't join my friends (friends list sometimes didn't even show
up). Before you read this paragraph and bash me for doing something wrong (which likely happened), I'll be the first to say my background in this kind of stuff is elementary at best. I went into my router and no ports had changed, so I deleted all the ports
off of it, still strict. Added the ports again, still strict. Went a little further and made a static IP for the Xbox, still strict. Attempted to put my Xbox in the DMZ (I didn't want to do that, but my friends were about to raid in Destiny and time was running
short...you get the picture), but failed with that and had to reset my router to default settings. Is there anything that immediately stands out that I'm doing wrong? I've been using portforward.com for instructions on how to do everything, and followed it
to a T. I don't know if I did something wrong on my end, if I need to contact Xbox, or if I need to contact my ISP. Any advice or help would be much appreciated. I have a Skype call with my brother who's great at this stuff later tonight to walk me through
it, but I'm sure he'd be appreciative if I could resolve it on my own. Thanks! Brent

:)

 

Ports not fixing NAT Type "open" on xbox one s.

I'd like to find a fix.

I setup xbox one s. First day it was "open" NAT type.

Second day and since, "strict" NAT Type.

No changes were made to modern/router. Until today, setup ports listed in support, verified them. And setup static ip to resolve. Worked on it all day to get it to say "open" as the NAT Type. Still shows as "strict", no change.

Gets online, connects fine. Will not allow headset chat since first day. Cannot find any resolution.

Please assist.

 

Please tell me it's not just me who can't get my NAT to open after trying EVERYTHING.

My NAT type is set to open on the one. I know randomly while playing the 360 and certain games it will tell me my NAT is strict. I have no clue why it used to bounce from strict to open. I always thought it was the servers from a specific game. I have
no clue on how to troubleshoot my router (gateway) if my NAT was ever set to strict on XB1

 

Sorry for my negligence - here's some more information:

What Country/State/Province do you live in? - Virginia

Modem brand & model number: None, just router

Router brand & model number: Actiontec MI424WR Rev. I

How many Xbox 360 and Xbox One consoles are connected to this router?: My Xbox One (wireless), roommate's Xbox One (wired), other roommate's Xbox 360 (wireless, never gets used)

Wired or Wireless (for each console): See above

Things you have tried: See original entry

Is UPnP Enabled? Yes/No/Unknown: Tried to enable it, but apparently the version of my router won't let you change it - can't find anything on whether or not it is enabled by default.

Do you have a NAT error? If so, what is your NAT type?: See above

Any Error Codes you encounter: When I try and test multiplayer connection I get "Can't get a Teredo IP address" (this is the first time it's happened).

Who is your ISP? (Internet Service Provider): Verizon FIOS 100/100