"Due to" and "because of" cannot be used interchangeably because they started differently in the language history. The phrase "because of " grew up as  and adverb while "due to" grew up as an adjective. As we can recall, adjective and adverb are two different parts of speech because adjective are words that modify nouns or pronouns while adverb are words that modify a verb, an adjective and another adverb. Basically these two terms cannot be used interchangeably for the reasons mentioned above. Moreover, "because of" is an adverbial preposition while "due to" is an adjectival preposition.

"due to" and becauase can not be used in interchangeable