@Azrul 

Hi, 

Please reset the modem by holding the reset pinhole for 10s to have a look;

if still the same, please help me check the following information:

What is the model number of the 4G sim card?

Did it work well on the smartphone?

Did you insert the sim card with the card holder together into the sim card slot?

If there is one more sim card, please have a test with a different one in case the sim card is the issue;

Thank you very much and wait for your reply.