Redmi k30i can make phone calls, but can't surf the Internet.

The reasons why this mobile phone can make calls but can't access the Internet are as follows:

1. Maybe the APN of the mobile network is not set correctly, and the mobile phone can't surf the Internet normally. You can find the settings of "network and internet" or "mobile network" in the settings of your mobile phone to see if the APN settings are correct.

2. It may be that the signal of the mobile network where the mobile phone is located is weak or unstable, which will also cause the mobile phone to be unable to access the Internet normally.

3. It may be that there is a hardware failure or a software problem in the mobile phone, which may also cause the mobile phone to be unable to access the Internet normally.