Unable to connect Chamberlain garage door opener via 5g internet

Mine is old NetGear N300 Model EX2700. I got it at least 5 year ago.

I do not think you need to buy a new extender. Your nighthawk extender should work. Your extender always tries to connect to the "Known" network it has connected to. You need to reset it to factory default setting. At that time, you will be able to pick Gateway network. You need to download a manual to follow the initial setup procedure after resetting to factory default. Trust me, t-mobile support would not know your extender better than you do. Incompatibility is an easy excuse to get you off the phone.

Your netgear should work also. But your extender might only work for 2.4 GHZ network as mine does. So you will need to separate 2.4 GHZ network out from default t-mobile gateway's hybrated network to create two networks for your t-mobile gateway. One for 2.4 GHZ, one for 5GHZ. At my home, 5GHZ is always much faster than 2.4 GHZ network. I have speed around 300 MBPS. So all my laptop/phone use 5GHZ network. But I leave this 2.4 GHZ for all the devices such as thermostat, smart devices. So far all works fine now.

I'm guessing T-Mobile has no interest in resolving this issue. Love everything else about it but this issue is forcing me to consider an alternative. So disappointed!

It has been a while since I last posted on this conversation.  Something really strange is going on either with Tmobile home internet or chamberlain or both parties.  MyQ mysterioulsy started working back in early April with no action on my part.  Then on April 29th, MyQ stopped working.   It has been that way since.  I reviewed by MyQ history and you can see breaks in garage door logging, usually for less than a week.  Like other posters on this thread, I really wish TMobile would address this lack of support.   

What I find even more distressing is not one TMobile support team member has even commented on this issue.  Argh!

I had the same issue. I found a great fix using the TP-Link RE200 AC750 wifi extender. Following the set up video from their website it has a way to configure for both 2.4g and 5g. I only set up for the 2.4 and skipped the 5g. Then I set my myQ garage door opener to that new established network and it works! I'm not tech savvy and found this as an easy and affordable fix. 

Has anyone used the wifi extender solution for MyQ with the Arcadian Gateway? Had no trouble with  Asus and TPLink routers in bridge mode but with the Arcardian Gateway can't get either to provide an internet connection.

Use an external router. Configure your router to use the SSID of your T-Mobile gateway. Delete the SSIDs from your T-Mobile gateway. Establish a new SSID in your T-Mobile gateway. Your IT equipments should automatically connect to the new router. MyQ garage you setup as instructed by the MyQ app and it will only detect the 2.4ghz connection. My setup is an ac3600 nighthawk $25 from eBay. 1000x better than the T-Mobile. 

I am not able to set up a wifi extender properly with either the Nokia or the Arcadian.

It sets up like one expects.  However, devices on the 'extender's wifi network' can connect to its wifi, but cannot connect through to the public internet.  A phone, for example, will say 'connected' but 'no Internet'.

No idea why y’all were able to connect  but I am not able to.

Netgear AC750 EX6100 extender.  Using only 2.4 GHz.

Just a follow-up to my previous post..
 

It looks like the Garage door opener can make a connection (to the outside world) via a WIRED connection on the T-Mobile gateway but not via the Wi-Fi put out by that gateway.

I say this because I can (ethernet) wire an access point to the T-M gateway, use a different SSID for the access point - and the opener connects fine through this access point.

(NOTE:  I used a NetGear Range Extender/Access Point configured as an access point).

Not a good long term solution, IMO - requires yet another device and a complicated set up.  T-Mobile needs to fix this issue with its gateway-WiFi.  Other service providers do not have this issue.  I may move to Verizon home internet soon.

SOLVED - If you use a repeater and then connect to that WiFi, the MyQ will connect.

I did get an extender - set up as a wireless access point - to work.  But in the end, all of these are just KLUDGES.   The T-Mobile Home Internet simply does not work as normal ISPs do.   I suspect this is simply because they are probably paranoid about how much bandwidth will get consumed. But there are other ways this gets limited in any case - which should be sufficient.  Poor design.  I strongly recommend using your own home router (connected to the THI gateway) to overcome a host of issues related to this T-Mobile design.

At some point I am going to try out Verizon mobile internet and see if it has similar issues.  I am not expecting that it does.