Why is the call console showing an unexpected country code?

Question

Why is the call console showing an unexpected or incorrect country code for an incoming call? It's not matching the country where the customer is calling in from.

Answer 

E.164 is the international telephone numbering plan that ensures each device on the PSTN has a globally unique number.

Examples of E.164 numbers:

E.164 format	Country code	Country	Subscriber number
[phone]	1	US	4155552671
[phone]	44	GB	2071838750
[phone]	55	BR	1155256325

When the dialling is done within the country, some carriers may not use the E.164 format, and therefore they don't add a country code.

This can cause that, for example, a call from [phone] appears in Zendesk as [phone]. As a result, the issue can cause numbers to be associated with the incorrect country code.