Can't Register My WhatsApp

WhatsApp isn’t sending me 6 digit's verification message. I am using active internet connection, my sim number is ok. I can talk to friends and family with my sim, I can install apps and get verification code easily with different apps. But WhatsApp isn’t sending me verification code. I have tried setting my sim to another phone, but still same thing is happening. No verification code came! I have also uninstalled my WhatsApp, then again I installed it. Same thing, no verification code came. But my sim is ok with every other apps in the world. And yes, I correctly wrote my sim number in WhatsApp while trying to register (with international code). Now what to do?

This is my number I have been trying to register. 

+8801*******

Another thing is, my Facebook also can't send me verification code in that particular sim! Such a ridiculous problem I must say.