Could you explain it? If you give more examples related to this situation, I'll be very delighted.
*****
NOT A TEACHER *****
Hello, Lemon-Tree:
This is what my teachers and books have taught me. (I have made up the example sentences.)
1. Sorry, boss. My late
arrival is
due to heavy traffic.
a. "due" is an adjective.
b. "due" refers to "arrival."
c. "to heavy traffic" is a prepositional phrase that modifies (belongs to) "due."
d. That sentence is NOT a very natural way to express that idea.
2. Sorry, boss. I
arrived late
because of heavy traffic.
a. "because of" is a two-part preposition.
b. 'because of heavy traffic" is a prepositional phrase that modifies the verb "arrived." (Why did you arrive late?)
3. Sorry, Boss. I
arrived late
due to heavy traffic.
a. Many native speakers now use "due to" in the same way in which they use "because of."
b. Traditionally, sentence #3 was considered "incorrect."
c. In 2016, it seems to be used and approved by almost everyone.
I noticed a few years ago, for example, that one of the best American schools for adult ESL students accepts the use of "due to" in place of "because of."