International roaming / India - has issues

I have been a T-Mobile ONE plan user since 2017. I have successfully used international roaming in Argentina, Brazil, Uruguay, Peru, Switzerland and the UK. As recently as 2019, I used international roaming in India with the IDEA network. 
I am in India right now in a not-small-at-all city called Pune. More people live here than in Michigan. Here, I have been getting Vodafone IDEA (Vi) India Talk and Text network but no data at all. It is such a struggle being abroad and not even being able to use Uber or Maps or Translate. I am not a heavy user at all so 2G speeds work very well for me as long as I can I can travel independently and safely. However with the current situation, that's just not possible. I have had to go and buy a different Indian SIM card for my visit.

My colleagues have told me that IDEA was taken over by Vodafone India in September 2020. Maybe this change is affecting our ability to use International Roaming Data on our T-Mobile plans. 

I am facing the same issue in Bhopal, India. My phone shows full bars but intermittent data connection. This is a complete farce. This was one of the main reasons and I switched to T-Mobile from AT&T and selected Magenta Max. This is not fair to the customer. I am okay with having 2G data speeds as long as it is consistent and I don't lose data.  But this is a joke what I am experiencing. T-Mobile can not make the claims of unlimited 2G data on international roaming if the service is not reliable at all. 

When you complain, be sure to mention that T-Mobile’s roaming maps show service in Pune and that they should either fix the roaming or the map.

I just landed in India a week ago and have been experiencing the same problems described by others here.

Phone shows LTE/4G full bars, and “Connected” in network status, but there is an exclamation point over the indicator icon, and all apps claim no internet available.

However, while trying different apps, I opened my work VPN (Cisco) and it gave a more detailed error message than just “no internet”, it said “DNS name lookup failed”.

Unfortunately, I did not have a terminal/ping utility on my phone, but using hotspot I was able to connect my laptop and behold, there was internet, but no name resolution
ping/nslookup google.com error
ping 8.8.8.8 worked fine

With that info, I changed the settings on my laptop to use google’s dns server (8.8.8.8) and had internet working at that point, albeit just via hotspot.

I could not see a way to force use of a specific DNS server on my phone (Pixel, android 12) for mobile data, just in manual wifi settings.
The private DNS feature only accepts a hostname, not an IP address, and so that too fails, since it can’t look up the new server to switch to in the first place… a bit of a silly limitation, I think.

Before India, I had been in Japan and Singapore, and had no issues with roaming at all.
So it seems that T-mobile’s own roaming data settings may have a DNS server that is often blocked within India for some reason.

Hopefully this helps some of you too, and maybe T-mobile can help fix this soon.

@BoulderColorado Thank you for these suggestions. Strangely, when I travelled to other cities like Trichy and small towns on the way, I was getting the LTE speed. After coming back I was getting LTE speed in some parts of Coimbatore and almost dead on other areas. Vi may not be too stable or strong in Coimbatore perhaps.

RESUELTO: Intl’l roaming add-on but no data (India)

this happens when the roaming partner selection is automatic and phone ends up selecting a partner that cannot extend roaming. I tried sim poping, restart phone, toggle airplane mode and each time phone selects Vi india while i am in Amrtisar. I found this because my wife's phone was somehow staying on the right one but mine did not. So, after i forced my phone on airtel with steps below, i got internet !!  T-Mobile won't have roaming with every small operator in India or Internationally. 

anyway an easy fix is — 

On the phone goto:

Step1: Cellular data > Network selection : change from automatic to manual selection (or disable auto)

Step2: Wait for list of roaming operator's to populate

Step3: select a national operator in your area (airtel worked for me in Amritsar for example)

You may need to restart phone after step3 And recheck step3 to make sure correct operator is actually selected. Once set it should remain until next restart or airplane mode.

Enjoy Magenta !

Problems when roaming in India are just par for the course. Do you have a PING utility on your phone? Try PINGing the numeric address "8.8.8.8" to see what happens.

There would be no advantage to Vodafone in not connecting your data.

Call International support at +1-505-998-3793 (free from your T-Mobile phone)

https://www.t-mobile.com/support/coverage/international-roaming-checklist

After  4 weeks  in India,  this problem  remains unsolved.  Numerous calls to  tech support resulted only in apologies  and  un-diagnosed  status.  Strangely,  when i moved to a big city  (called  Bangalore), i experienced  no  issues on the first day,   same  "no data connection"  on  second  day,  and then  it started  working  fine  later part of  2nd day.  It was working  in  Delhi  during my  initial  landing.   But,  the  city  of  Coimbatore  consistently  had  "no  data connection"  for  3 weeks.   Talked to local partner, and  they  tried to connect the  phone  directly  to their   APN.   No  luck.  T-mobile  just said   "tower  issue"   and  left  it at that.   This  would be  another  blow  to  account,  since  I will have to visit  this  city  of  Coimbatore  often  in future  and  I  would require  connection  (as  a  backup).   It maybe  was bumped  upto  Engineering  (with a  trouble ticket  assigned),  but  no  call or email from them.   They  simply   overwhelmed  after  the  recent   security  breach.

What  can i do  to  get this resolved ?

I have the same stupid issue in a place called Trichy and it's the same answer - Tower problem. It's pathetic and I feel, TMobile has to do something. On call with Tmobile.

6  hours  phone call  and  1  month  later,  this problem  is  not yet  solved.  I  travelled  to  a  bigger  city  (Bangalore)  and  4G data  worked  there fine.  When  i  travel  back to  Coimbatore,  my  data  connection  does  not happen  (even though  signal  is  strong  and  i am  at center of city).   The  phone  i have  is a   LG  Q7+  (T mobile)   running   Android  9   software  version   Q610TA20g,   

Wonder  if  people  who have   a  Samsung  also  have this issue  in  Indian  small  towns.   Last  time i travelled to  India,  (2 years ago)  this was  not an  issue.