MyQ (Chamberlain) garage door and Gateway 5G router not compatible

I think you could get it going with the second network with different security settings than the first network.  I understand that is more than you want to tackle by yourself.  Please ask a tech-savvy friend to help you; follow the instructions in my post on page 1 of this thread (the last post on page 1).  That is Step 1.  Then, Step 2 will be getting the home security and/or garage door opener connected.  I can’t help with that.

The alternative is to try another internet provider.  

Good luck.  

Same issue here. I went to forward port 8883 and I cannot even login using 192.168.12.1

If you have the Arcadyan or Sagemcon gateway you have to manage it via the mobile application. Only the Nokia gateway or the 4G LTE gateway from T-Mobile allow the web GUI access for management. T-Mobile does not provide port forwarding options due to the architecture of their network. They use an IPv6 network and 464XLAT and just don’t support port forwarding options. With some VPN solutions you might find a way around the issue but it entails additional cost and work to get the functionality.

I was trying to use a cable modem! Dug out an old ASUS that Sprint had given me, linked it to the TM gateway, fired it up, and MyQ liked connecting pretty easily! No need to buy new equipment!

@fitisit2012  If I understand correctly, your home security system was working with the first gateway.  So the technician should not have said “nobody has T-Mobile internet” or that Vivint doesn’t work with T-Mobile internet.  Do you remember if the first gateway had more than one Wi-Fi network? They come with one, but more can be added.  Many people have added a second network to handle garage door openers, printers, older computers, etc.  Your first gateway might have had that, and now your Vivint system can’t find it because it doesn’t exist (yet) on the replacement gateway.  Please read the instructions for creating a second network in my post which is the last one on Page 1.  Do you remember if you or someone else did that before?  Do you know the SSID (network name) and password that the system was using?  If you can remember, make a new network on the new gateway with the same SSID and password as before.  If you can’t remember, you should go through these steps -- but you will also need to connect the security system to the new network.  You may have to have the technician return.  You might need to show him the T-Mobile Internet (or T Life) app on your phone.  Avoid changing any settings for the first network which I am assuming is working for other devices in your home.

I’m sorry.  Unfortunately, I have never heard of a T-Mobile tech going to a home.  You might ask a tech-savvy neighbor or friend to help.

Just tell me, did it work before, with the first T-Mobile Home Internet gateway? 

No  it didn't work with the first or 2nd router and Vivint is telling me Tmobile internet doesn't work with Vivint home security.

Did you disable DHCP on the TP-Link Router? Only one device on a network can operate as a DHCP server to hand out IP addresses.

If you want to use the TP-Link for wireless, I'd put it into access point mode (AP), but if you're trying to get the garage unit to communicate with your WiFi network, why not just create a new network on your T-Mobile gateway as I described above. From what you've described, you don't need a separate router., maybe just a WiFi extender.

I’ve linked the TMobile gateway with an Arris router. I don’t see anything new to connect the MyQ. Do I need to configure something new on the router to chose while connecting the MyQ?

Sounds like you have your problem solved, but if you're using a TP-Link WiFi Extender, you can only create a connection with the 2.4 MHz band at WPA2 security. Why not just separate the 5 MHz and 2.4 MHz  bands on the T-Mobile gateway, give them separate names, and have the Nexx devices connect? I also have a Nexx garage door opener (V1) and had no issue with its connection.

Here is a possible workaround to your problem.

Create a new network in the T-Mobile app. Give it a different name (SSID) than your primary network, configure the frequency as 2.4 MHz only, and choose WPA/WPA2 as the WPA version. 

Also be aware that some extenders use a form of NAT to connect to your network. I have a Netgear EX2700 that I've been using successfully for a long time, but with T-Mobile, while it still works as an extender, it does not have a unique IP address so that I can access the configuration page.