[Resolved] Other language shows

Background of the issue:
I am trying to publish the English version of my site for the first time. Previously, it was hidden. English pages won't show although they are published. Instead there shows "Page under maintenance" or "Page seem not exist".

Symptoms:
Some pages show a 'Site under maintenance' page (like Home page), which is a draft and not published. Other pages display 'This page seems not to exist'.

Questions:
Do I have some setting wrong?
Why are the published English pages not showing?