Currently, due to the Golden Week vacation period in Japan, we are unavailable for correspondance until 5/11.
Currently, we are unavailable for correspondance until 5/11.
現在、(私たちは)5/11まで対応が出来ません。
"unavailable for correspondance" は対応が出来ませんと言う意味の "unable to correspond" よりもっと丁寧な言い方ですのでビジネスメールには合います。
理由(due to the Golden Week period in Japan)「日本でのGW期間の為」を入れると:
Currently, due to the Golden Week vacation period in Japan, we are unavailable for correspondance until 5/11.