The reason may be down to a Three UK network fault, ​@Blicjo. 

I also can’t make or receive calls-location Aberdeen 

my wife has smarts and it's the same, it started at the same time

Hi ​@Blicjo and ​@George Morrice 

Thank you for getting in touch. 

We're aware of a network wide issue affecting services, unfortunately we do not have a time frame of when this will be resolved.

We apologise for any inconvenience caused and want to assure you this is high priority and our team are working hard to get this repaired as quickly as possible.

All updates are available to view here. 

Thanks, 

Nat 

Now operational 🙏

Hey all​​​​​​,

We’ve had confirmation that the issue is now fully resolved, and calls are functioning as expected. Thank you for your patience and we apologise for any inconvenience this has caused you.  

If you’re still unable to make or receive calls, please try restarting your phone, or toggling Airplane Mode on and off.

For latest updates, please see:

https://community.idmobile.co.uk/contacting-id-183/some-customers-are-unable-to-make-or-receive-calls-72269

Thanks,

Tyler