In the modern English usage because of and due to can be used inter-changeably.
The trains were cancelled because of the rains.
The trains were cancelled due to the rains.
However, it is generally advised to use 'due to' between a sentence after a noun or verb to be. 'Because' can be used at the beginning of a sentence while using 'due to' in the beginning of a sentence is not advised and deemed wrong by experts.
Because you helped me, I am going to repay you.
Because I love you, I shall do that for you.
The plane is due to arrive at 8 pm.
He succumbed to his liver infection due to his drinking habits.
He succumbed to his liver infection because of his drinking habits.