Carrier T-Mobile Carrier signal drops at random

[mamut]

Hello, I am on T Mobile and this is my issue

I use 4G and sometimes It just stops working. When mobile data over 4G stops working, there still is 4G on the top of the screen, it doesn't say ''nos ervice'', it's normally saying that it is on 4G but can't browse internet or use whatsapp.

Then I need tor estart phone and it works again

is it hw or sw issue? I did reset of network settings and tried airplane mode but nothing. Internet over 4G just ''freezes''

what to do?