Symptoms
I am trying to change the default language for reseller in OA, but it resets back to Dutch. What I would like to achieve is log in under the reseller Brand URL with English language.
Cause
In reseller brand interface settings the option Allow to select language
is set to Use the same language as login screen
and login screen is set to use Dutch language.
Resolution
Set the option Allow to select language
to user can select language on login screen
to make the language selection available at login screen of reseller Brand URL.
Set the Login screen language to English
if you want the English language to be used at the login screen.
Above setting can be changed at Reseller Control Panel > System > Settings > Brands > brand name > Interface settings tab. See additional information in OA 5.5 documentation and in OA 6.0 documentation.