Hi, I've recently helped my father to sign up to a sim only 1 month contract package to ID mobile, but his phone (Sony Xperia 1 II, 2020 model, on Android 10) is having problems with the sim card, it's only partially working. My father is elderly and not very good with technology so anything technical or advanced then I have to help to setup/solve for him, so I'm helping him to setup this new ID Mobile sim in his phone.

When the sim card was first inserted into the phone on Thursday, there was no signal (zero bars), and said Emergency calls only, then after a few minutes, it finally found the signal, full bars, then it says LTE+ (at our home address unfortunately there is no 5G). 

Then I tested to see whether it can make calls or received calls, and also whether it can send or received sms text messages, but unfortunately both functions are NOT working. When I tried to make a phone call, there is no dialling tone, just silence for about 10-15 seconds, then it just says "Mobile network not available" on screen, even though on the top right corner of the screen it's showing full bars of signal and showing LTE+. When I tried to call this (temporary) new number from my phone, it just goes straight to the network message saying "07********* can't take your call right now, please leave a message after the tone".

Same for text message, when trying to send a text, it just says "Wating for connection", then after a while it just says message not sent. Also when I tried to send text to this new sim/number using my own phone, nothing happens, no confirmation on my phone, and no message on my father's new (temporary) sim/number. 

So the phone call and sms text message functions are both NOT working on my father's phone.
 
However, the LTE+/4G mobile data internet connection is seemingly working, I can browse the internet, different websites, watch youtube etc on mobile data, and can also make and receive calls using WhatsApp call, so there is mobile data internet (LTE/4G) connection. But a little strange behaviour is that when I tried to do a speedtest using the Ookla Speed Test app it says "Error, test failed to complete, please check your connection and try again", whereas if I use the google speed test on the Chrome browser, it can complete the speedtest and showing fast LTE/4G speed.   

I've tried removing and reinserting the sims multiple times, and have also restarted the phone multiple times, the phone call and text message functions are still NOT working. Also another strange behaviour is every time that I restart the phone, it shows no signal (0 bars) and Emergency calls only again, and it can take upto 10 minutes before it regains the signal (full bars), LTE+ logo, it then stays like that (strong signal full bars, LTE+, working mobile data internet) consistently as long as I don't restart the phone. But the original problem remains, LTE/4G mobile data internet works, but phone calls and text message NOT working. (We've never encountered this problem with any other provider before, whenever we restart the phone, the signal usually connects within seconds).

Personally I've been with ID mobile since last year (I switched over from Sky Mobile), my phone is the Sony Xperia 10 VI (it's a 2024 model, on Android 14), which has been working fine with the ID mobile sim since day 1, that's why I thought the process of helping my father to switch over from his current provider (Lebara) would also be quite easy, but unfortunately that's not the case, we've ran into quite a technical problem.

My father's phone (Sony Xperia 1 II, 2020 model, on android 10) is clearly compatible with ID mobile network, based on the links here:
https://community.idmobile.co.uk/help-with-your-phone-206/what-phones-are-compatible-with-the-id-mobile-network-67490
https://community.idmobile.co.uk/help-with-your-phone-206/is-my-phone-compatible-with-5g-43705

Ironically my phone (Sony Xperia 10 VI 2024 model, on android 14) is not mentioned in your compatibility list, and yet it's been working fine since day 1 when I got the ID mobile sim last year.

I wanted to help my father to switch over from his current provider Lebara to ID Mobile, (very importantly wanting to keep his old number). So I need to start the porting process, and because I chose to do the porting after receiving the sim card (don't want start the porting during checkout), but in order to start the porting process, I need to first add this new (temporary) number to his ID mobile account first, but because his phone (with the new ID Mobile sim) currently can't send or received text message, he can't receive the verification code that's needed when trying to add the new (temporary number), so can't complete the add number to account process, so can't start the porting process.

I've done the porting process myself last year to my own phone, back then I don't think I actually needed to verify/or add the temporary number to my ID Mobile account first, after receiving the sim card, I think I just started the porting process online, waited till ID mobile confirmed via email the porting is complete, (and my Sky Mobile sim stopped working), then I inserted the ID Mobile sim into my phone and all the functions (phone calls, text message, mobile data internet) started working straight away. 

My father's phone is purchased here in the UK in 2020, originally from O2, and it came already unlocked, and since then he has used multiple MVNO providers like Sky Mobile, PlusNet, CMLink, and currently Lebara, and all of these sims started working from day 1 when inserted into the phone, but it's really perplexing why the ID Mobile sim is only partially working.

Also just for testing purposes I inserted my father's new ID Mobile sim into my phone (Xperia 10 VI), and all 3 functions (phone calls, text message, mobile data) are working fine on my phone, so it seems there maybe a technical/specific issue with the phone (Xperia 1 II) settings and the ID Mobile network? 

So I've done some googling and research online, and it seems this problem might have to do with VoLTE/4G calling settings? but on my father's phone (Xperia 1 II, android 10) there doesn't seem to be any way to change this setting, it seems to be all automatically selected by the phone or the network?

As I said before this phone (Xperia 1 II) has used multiple MVNO network sims since 2020 (Sky Mobile, Plusnet, CMLink, Lebara), all of them worked straight way, no need to change any settings on the phone, all done automatically.

So I wonder is there anything you can do on your side to solve this problem? networking settings, account settings etc?  

It's a very frustrating problem/situation, because even though personally I'm happy enough since I switched over to ID Mobile last year (hence why I also recommended my father to switch over), but I never thought we would run into this technical problem, and it's now all relying on me to sort it out, very time and energy consuming, and if we can't sort this out, we would be forced to cancel this contract within the 14 days cooling off periods, which is very upsetting after spending so much time and effort on comparing packages, ordering, setting up, running into and then trying to solve this problem, all this effort wasted.

Please help, thanks.