Can't make or receive calls

[RobertV_1974430]

It's been a few days now that I can't make any calls and the incoming call don't reach me, I always get the missed call message after, even if I have full signal, Internet is OK but no calls 

[SmartyTrousers]

I suspect Three have now turned off 3G in your area, and your phone either doesn't support VoLTE (calling over 4G), or has the setting for it turned off, or supports VoLTE but is not compatible with Smarty's VoLTE specifically.

[RobertV_1974430]

ive already done that , i have a sony 1 , it supports everething and it is not loked in any network , also tryed difrent devices and still the same 

[SmartyTrousers]

Already done what?

If you mean a Sony Xperia 1, that handset is on Smarty's list of devices which are not compatible with VoLTE on Smarty: https://help.smarty.co.uk/en/articles/8985136-checking-if-your-device-is-4g-volte-compatible

[RobertV_1974430]

i see , ill swith then .... to bad i had 2 sims with smarty 

[Decembersangel]

Hi @RobertV_1974430 👋
Your phone is not supported by SMARTY (accordingly to their list)
 https://help.smarty.co.uk/en/articles/8985136-checking-if-your-device-is-4g-volte-compatible
You need to see 'LTE' in the Settings for 'Prefered Network Type' to use the 'VoLTE' network.
If you don't see LTE then dial *#*#4636#*#* on the phone keypad and it should take you to a screen that shows if VoLTE is enabled (or the option to) on your phone. If it is 'greyed out' (but the option is there, as seen at the top of this post) 
https://www.reddit.com/r/SonyXperia/comments/zxvssp/sony_xperia_1_iii_xqbc52_volte_support_it_remain...
then that may mean that your software/firmware needs updating to enable it.

If this is the case you will need to do research to find the answer on how to do this (which may be relatively easy to do) as there is a lot of information/help out there.