WiFi Calling on T-Mobile network by other MVNO: ERR081

memn1

    Hi,

     

    I'm using a MVNO that uses T-Mobile network.  The phone I use is a T-Mobile phone that has WiFi calling feature. 

     

    Should WiFi calling work under any MVNO that uses T-Mobile network on a T-Mobile phone that has WiFi feature?  Right now it's giving me an ERR081 on the WiFi Calling.

     

    If I put in a T-Mobile postpaid SIM on that phone instead, WiFi calling works totally fine.

     

    Thanks.

      All replies

      • tidbits

        MVNO don't offer full features as if you actually go with the provider itself. There are probably other restrictions often MVNOs don't tell you about.

        1 of 1 people found this helpful
          • memn1

            I thought WiFi Calling feature is purely on the phone's software (and firmware)? 

             

            Or I'm missing some additional details about WiFi calling?

              • tidbits

                Still needs to connect to T-Mobiles servers even is the point of connection started with wifi. If the MVNO has no agreement with the respected main carrier you will not get full features. For example iirc some MVNO offer no more than 8Mb/s data speeds, and no VoLTE.

                  • memn1

                    In my case, regular Voice call (non-WiFi calling) worked fine going thru' T-Mobile network. 

                     

                    WiFi calling should have no dependency on carrier (cell) network.  So this is a surprise to me.  This would be pretty tight dependency of WiFi calling feature to the carrier network. 



                    I have my own WiFi network, I should be able to use and enjoy this feature if phone supports WiFi calling already -- and not to worry about more requirements imposed by T-Mobile cell network?


                     

                    T-Mobile should not interfere with a feature this way, where the WiFi network is purely provided by the customer's own WiFi network (or any other 3rd-party/public WiFi network).

                     

                    (I know the carrier would count minutes when using WiFi calling, so I know the carrier is not totally independent when making WiFi calling already).

                     

                    I noticed, for example, when I had a prepaid T-Mobile SIM and the account was closed, I'd see same ERR081 for WiFi Calling feature when that SIM was inserted. 

                     

                    I wonder if MVNO SIMs are not considered 'T-Mobile' accounts, and hence WiFi calling is not allowed.  I would think it should not be that way.

                     

                     

                    This would make the WiFi calling feature pretty bound to carrier account only (I haven't tried using phone's WiFi Calling feature of a T-Mobile phone on, say, ATT network with ATT account -- to test out the other scenario).

                     

                     

                    Again I'm not sure if our thinking is correct, or actually it's something else (misconfiguration). 


                    Someone or an engineer who might know the specifics of WiFi calling perhaps can shed some light in this... .

                      • memn1

                        A more common situation is,

                         

                        would a T-Mobile phone's WiFi calling feature work -- when I'm travelling overseas and put in a local SIM card?

                         

                        I hope it does -- but it sounds like it won't, with the error I'm seeing now.

                          • tidbits

                            memn1 wrote:

                             

                            A more common situation is,

                             

                            would a T-Mobile phone's WiFi calling feature work -- when I'm travelling overseas and put in a local SIM card?

                             

                            I hope it does -- but it sounds like it won't, with the error I'm seeing now.

                            No it will not.  Wifi calling requires carrier credentials and standards.  Not all carriers use the same standards.

                          • tidbits

                            No configuration going to fix the issue.  What agreement the MVNO has made with the MVNO is between them and what you want from the MVNO they may have not worked an agreement.  Even if you use the T-Mobile network you are not a customer of theirs, but that of the MVNO.  If the MVNO offers wifi calling in an advertisements then the MVNO needs to contact T-Mobile to get it fixed for you OR they never offered it and needs to update their websites.