I have an intranet web application developed using C# and .NET and it is hosted on our own internal webserver running IIS 8.5.

I have it set up the application pool to use the built in account `ApplicationPoolIdentity` and this works fine. 

However I need the application to be able to browse a network drive so I have changed the application pool to use a custom account that has access to the network drive. I know it has access as I am using my login details here.

But when I browse to the website I get the following error

> 
> **Service Unavailable**
> 
> 
> HTTP Error 503. The service is unavailable.
> 
> 
> 

When I recycle the application pool with these new settings I get the following error:

> 
> There was an error while performing this operation Details The object
>  identifier does not represent a valid object. (Exception from HRESULT:
>  0x800710D8)
> 
> 
> 

I have also tried using the server admin account but I get the same error messages.

Thanks

**Edit**

The following message is in the event log

> 
> The identity of application pool TestApplicationPool is invalid. The
>  user name or password that is specified for the identity may be
>  incorrect, or the user may not have batch logon rights. If the
>  identity is not corrected, the application pool will be disabled when
>  the application pool receives its first request. If batch logon
>  rights are causing the problem, the identity in the IIS configuration
>  store must be changed after rights have been granted before Windows
>  Process Activation Service (WAS) can retry the logon. If the identity
>  remains invalid after the first request for the application pool is
>  processed, the application pool will be disabled. The data field
>  contains the error number.
> 
> 
>