Why can't tg telegram receive the verification code?

International short message service has not been opened, network delay and system problems.

1. International SMS service is not enabled: Telegram is a foreign software, and the international SMS service is not enabled on the mobile phone number, so you will not receive the verification code.

2. Network delay: When receiving the verification code, the current network delay will lead to the failure of reception.

3. System problem: The busy telegraph server or system failure will make it impossible to receive the verification code.