Gateway 5G

@DRM when you say the box says excellent connection, do you mean the 5 bar led display on the front of your gateway? The internet connection signal provides the display data so if you have more than 1 bar you will have internet access. 
 

Please describe your home network design. Is your T-Mobile gateway the way your devices connect to your home network (assuming we are talking about your home network vs your workplace)? Or do you have a Wi-Fi router connected to your gateway and have your devices connect to the Wi-Fi router? 
 

Please let us know. 

YES, I KNOW  the bars on the 5G Gateway are SUPPOSED to indicate the strength of the 5G INTERNET  connection. What they REALLY  indicate is the strength of the connection to the T-Mobile tower/source.  I have 4/5 bars on the GATEWAY and as I have discussed with customer service numerous times, that I still have NO INTERNET CONNECTION.  The devices (Including my S23 ultra) all say "CONNECTED,  NO INTERNET". AND I cannot go online. Sometimes, after 10 to 30 or more minutes I can "RESET YOUR GATEWAY" from the Gateway application and sometimes it will reconnect to internet service.

@DRM Thank you for the response. I know some of my questions read very basic, but it helps with the diagnosing (my apologies). 

If you have 4+ bars on your signal strength LED and internet connectivity is spotty, that sounds like an internal gateway issue. I recommend you take it in to your local TM store and ask for an exchange. 

Let us know what happens.

Customer service was "going to finish testing their equipment and then exchange my Gateway.  I will just go to my local store and see if they will exchange it

Gracias

IMHO, it sounds like you are having a "authorization" problem. What you are describing happens when the signal/connectivity is good, but the gateway, and or devices have not properly "logged in" with each other. (I'm speaking from over 3 years of experience dealing with these T-Mo 5G gateways.)

I suggest doing a factory reset on the gateway (stick a paperclip in the reset hole on the gateway, and keep it pressed in for 10 seconds then release).

Then use the T-Mo Home Internet app to set up the gateway. Important thing to remember, is to CHANGE the SSID and passwords on the gateway, and then use those NEW names & passwords on your devices.

Also  sometimes the app makes the changes on the gateway correctly... Sometimes it doesn't. When it doesn't, in my experience, you get the problem you have - connection, but no internet. ¡Buena suerte! 

@WhiteDolfin good point about the factory reset and changing the SSID and password to ensure the new authorization connectivity. 

Good idea. 

Thanks for suggestions.  I reset (factory and regular) Gateway 3 different times while on the phone with customer service!  It seems that even though they can call up my previous discussions,  they want to walk through the same troubleshooting steps before moving on, even if you EXPLAIN how many times you have done the same steps! 

I plan on exchanging boxes this week. But, I say BUT!!!, I THINKIT IS A INTERFERENCE PROBLEM with the Navy E/F 18's and their electronic altimeter!  It also is using a frequency that CAN POSSIBLY interfere with the 5G network.  I had the service representative State this in one of my call in's. He didn't want to, but 3 planes (I am in the final landing approach to the base 2+/_ miles away) came by doing their 3 "touch and go" landings and 1/2 way through the Gateway lost INTERNET CONNECTION! 

THIS HAS HAPPENED before, 1 or 2 planes maybe ok, but multiples close together and it has happened. Then it may take 15 minutes to ????? Longer for internet connection to resume,  this INCLUDES MY INTERNET CONNECTION  ON MY S23 ULTRA, I can make phone calls,but NO INTERNET. 

T-MOBILE towers are within 2 miles from my house and ALSO IN THE LANDING PATTERN.

Will post results later. OBTW no flights this weekend and no problem with internet!  Plus, SUPPOSEDLY they did some maintenance on my local towers last week.

GOD BLESS AMERICA!  HAPPY INDEPENDENCE DAY!