"It has two languages."

I don't really know what you mean by that.

You need to be more specific about what changes you made to configure your sites for different languages and steps to produce the problem.

By "Cambodian Language" I guess you mean Khmer.

When I set my web browser language preference to Khmer I am still able to login at demo.mojoportal.com

I suggest also check the error log for any related errors when login fails.