When using $wgDBWindowsAuthentication [option "Windows Authentication"] in the WebInstaller, $wgDBuser is left empty. This causes that no connection is created in DataBase::__construct() and the consequence is that we get an error message telling us that it cannot connect to the database (despite it could in theory) when attempting to access the main page.
Result:
------------- ------------- Sorry! This site is experiencing technical difficulties. Try waiting a few minutes and reloading. (Cannot contact the database server) -------------------------------------------------------------------------------- ------------- -------------
Expected result:
Working wiki despite no DB user name.
Woraround:
Set a dummy user name.