Spent hours on the phone, no help. Tmobile is going to get a field engineer involved.
wow
I have their newest gateway, I think that might be the issue. They made a mistake and sent me two of them, so they had me unbox and try the second one out, no go, still connection 3 for the dc.
I will add my experience here for what it is worthā¦
I ran T-Mobile internet for a year and a half with no issue. That being said here was my setup, not as a suggestion, but maybe a clue.
T-Mobile router/wifi was placed in front of a pfsense firewall that also acted as the router for my main network.
Behind that was was an Aruba wifi mesh system, Yarbo connected to this.
The pfsense handed out IP addresses so things were effectively Triple natted which is of course not ideal, but it worked with no issue to Yarbo, I assume that there is some tunneling to Yarbo that goes on.
Although on a mesh I could reliably use Yarbo even with connection to wifi - note I know Bryan says donāt do this. I had little issue and in some ways worked better. Also note that I have a large mesh with outside APs. Arubas are enterprise grade, they are older but have plenty of bandwidth for Yarbo, but not the blazing fast speeds of newer systems.
I do suspect in your case there may be some firewall in the T-Mobile router that may be causing a block.
Also note if you are running anything like pihole or a dns blocker that could certainly cause issues.
You might try to change dns to something like google 8.8.8.8 and see if that fixes it.
Again most things now days try to create a tunnel as multiple nats can reek havocā¦
The problem is with the newer gateway from tmobile, you canāt change any settings, they dumbed it down to setting your wifi name and password.
I tried a mesh, that did not work. I want to try a wifi bridge, but canāt find any local.
Really frustrates me when companies do this. I get simplicity for the sake of the inexperienced or users who donāt care. But, get me an advanced mode to tweak all the knobs.
Good luck, their support is wellā¦some one reading from a screen. Hopefully @Yarbo-Forum can chime in here. Maybe @bryan.wheeler
Is there a place someone can change the dns of the DC? Yarbo?
Other than that you might want to try to change the DNS for your DHCP server to google 8.8.8.8
Have you checked the equipment to see that the DC and Yarbo get an ip address?
I say this as I know many people put things in line like dns blockers (pi hole for example) and this can certainly interfereā¦
No there isnāt. Yarbo seems to hard code some DNS servers into their systems instead of respecting what is handed out from DHCP. This is a really bad practice for reasons like you mention.
If you have a mesh, will it work in router mode? That is it hands out its own IP and does NAT to the T-Mobile/WAN interface.
Again adding nats is not ideal, but on T-Mobile you are already multi natted so it does not matter.
Again, not for the layman. I ran a vpn for items I wanted a non nat public ip for. I canāt really explain this on a forumn. Inline equipment is needed (like my pfsense) to make it happen. I did not have to do this though.
I did switch to the new gateway just 6 months ago, I got Alta fiber 2 months ago. I had no issue with that T-Mobile gateway either, could be something newer. I never messed with the T-Mobile as it just handed an ip to my main router.
Ok, thanks. I tried to find it myself, but not real hard. Indeed it should be settable. Thanks Bryan in to the memory bank that goes 
Just out of curiosity, Netgear has their dumb mobile app but if you go to your Gateways IP address on a web browser, you can login and do a lot more things. Maybe the T-Mobile Gateway is like this. My FIOS router is the same way. Mobile app is pretty limited but you can get into the web interface and do a lot. Even an advanced mode to do more in that web interface.
If you log in the ip of the tmobile gateway it gives you even less info, lol.
The web interface basically tells you if you have internet or not, thats it.
I just took the mesh system and connected it as from the factory, it is a TP-link, had it for many years with my starlink to get internet wifi in my shop
I am not a network guy at all, I am an electrician by trade. I know enough about networking as pulling cable and putting ends on, lol.
Does it have 2 ports?
Often one is wan - excepts an ip.
Many mesh systems has a master and that is the one that would have 2 ports. If one connects to the master often there is options to configure as I say. Again just throwing out clues just got off of vacation.
Second is lan and can be enabled to hand out ip. Although, I am IT, I can support many things, I certainly do not know all equipment and of course just trying to assist.
I know some the rj45 even as single can be a wan, as the others are just in through the mesh. Those are the cheaper unitsā¦
Itās a tp link deco x20. All the extenders have 2 ports, just labeled 1 and 2
Operation mode it has a choice of wifi router or access point, I had it on wifi router
Ok those are pretty decent units. You can certainly do this. I donāt run them although I did look at them for my home. Maybe in the app or connecting to them you can set this. I will try to look it up.