Hello @Sbalram 

Are all the lights green on the T-Mobile router and is internet via cable working normally?

Are you using another router or extender for the WiFi or are you only using the T-Mobile router?

I experience this problem always, the internet drops and reconnects.. i don't get uninterrupted internet at all..

Yes, all lights are green.

I always use  internet via wifi, not wired.

No other router or extender is used ,only the modern which t mobile provided.. 

My observation is everyday around 10, 12 and 15 and 16 the internet drops and reconnects.. today was worse.. it was never reconnected for 20 mins and i missed my office calls.

May be the modem is quite old .. i am using this from 2019 for both dsl and fiberglass same modem..i thought it would be better with fiberglass but no same problem..

@Sbalram 

You habe a Fiber connection?

You could perform a factory reset by pressing the reset button on the back of the router for about 10 seconds using a small object.

Yes, i have fiber connection.

I did factory reset already, but no luck.

Same problem continues 

Hi @Sbalram, thanks a lot for letting us know! I can't see anything strange in your connection, but the fact that you're experiencing problems says enough. So I'm going to help you right away to make the connection way more stable. Because you shouldn't experience issues everyday. Can you please perform a speedtest near the modem with Fast.com? Is the speed okay? I just turned the bandsteering off on the modem. Did this help for your connection?

Same problem happened today again.. poor network connection and also it also drops intermittently.. can you check ? Thanks 

@Sbalram

What could be the cause (suggested solution below)
 

When using WiFi in an urban environment you may notice unstable connections.

For the commonly used “2.4” wifi range, your modem/router can only choose between 11 so called channels to use for communicating with your devices.
When the modem/router detects that it is busy with traffic (neighbors using wifi also) on the used channel it may automatically change its own settings and select another channel.

As the options are limited (11 channels) this may result in your modem/router constantly trying to adapt/adjust. This will result in unstable wireless internet.

Solution

You can change the settings in your modem/router to not ‘automatically’ choose the ‘best’ channel.
Change this setting and select a channel yourself. For example, ‘3’ or ‘11’.
Try this first.
Having done this removes the auto-adjusting and instability as a result.
The downside is having selected an overused channel so if it obviously turns worse, pick another channel.
A quick Google search provides loads of information, for example → "WiFi channels explained"

You can change the settings by logging in to your modem/router via a browser.
 

Another option is to force your devices to connect via the 2.4 wifi alternative; 5.
This has a broader distribution of to be used channels but is less extensive in range.
As this takes more effort, I would suggest trying the above option first.