Thai marks the result as well as the reason, and the two halves have to match. เพราะ gives the reason straight after the result, the same order English uses. Put the reason first and it becomes เพราะว่า … เลย, where เลย carries the sense of ‘so…’ that introduces what followed. เนื่องจาก is the formal one — announcements, notices, the news — and its partner is จึง, not เลย. Getting the pairing wrong is the commonest slip here.