because of
prep. phr..prep. phr.. You use this to give the reason for something. It connects a result to its cause.
prep. phr.. A compound preposition that introduces a noun phrase functioning as the cause or reason for the action or state in the main clause.
The game is cancelled because of the rain.
We were late for the meeting because of the terrible traffic on the motorway.
The project's success was largely because of her tireless dedication and refusal to accept mediocrity from her team.
This phrase is always followed by a noun or noun phrase, not a full sentence.
Contrast directly with 'because', which is a conjunction and must be followed by a full clause (subject + verb).
We stayed inside because of it was raining.We stayed inside because of the rain.'Because of' must be followed by a noun phrase, while 'because' is followed by a full clause.