It was more popular than expected, and we cannot accept any more reservations.
予想以上 – more than expected
人気 – popular
これ以上 – any more
予約 – reservations
受け入れられない – cannot accept
満員のイベントに、問合せが来て
An inquiry came for a full-capacity event.
他に役立つ文章:
次回のイベントがある際にご連絡ください - Please contact us when we have our next event.
日本 
