asp.net - 401 - Unauthorized: Access is denied due to invalid credentials -

asp.net - 401 - Unauthorized: Access is denied due to invalid credentials -

i having issue i've got asp.net mvc4 application beingness published via web deploy our staging server. behavior seeing that, when accessed staging server itself, app operates fine, when accessed remote device, error 401 - unauthorized: access denied due invalid credentials.

where things weird me if open iis on staging server: -> select site -> click on error pages -> edit feature settings -> select detailed errors 1 time "detailed errors selected, remote browser begins work fine. toggle errors flavor of "custom", remote browser fails again.

to add together insult injury, nil beingness caught elmah, nor staging server event logs, nor iis logs.

how can resolve error when turning on "detailed errors" seems somehow resolve issue. obviously, reply not leave "detailed errors" on....

thanks.

update #1

based on reply referenced @sarhdan, discovered had in shared layout phone call action on controller had been placed in controller wide [authorize]. so, whenever forced head login page, consumed layout, got bit of circular dependency...it can't render login page, because i'm not logged in, can't access resource needed render login page......

bonus question offer points :d:

why "detailed errors" setting cause error "magically" resolve...the actual issue still there, , should still generating error...... ?

asp.net asp.net-mvc iis iis-6