Fix for Object reference not set to an instance of an object error when configuring SharePoint 2013 App URLs

When trying to configure App urls from SharePoint 2013 central admin you might encounter the dreaded error “Object reference not set to an instance of an object”.

 

 Most common reason for the error is that you are trying to configure App settings without creating service applications and corresponding proxies for App Management Service and Microsoft SharePoint Foundation Subscription Settings Service.

 Below are the steps to fix the issue

1.       Start the App Management Service from central administration.

2.       Start the Microsoft SharePoint Foundation Subscription Settings Service from central administration.

3.       Configure the App Management service application and proxy from central administration or PowerShell

4.       Configure the Subscription Settings service application and proxy from PowerShell

 

Detail steps for  configuring App environment is available in the technet article http://technet.microsoft.com/en-us/library/fp161236.aspx

Fix for disabled New Web Application button in SharePoint 2013

Sometimes after a new installation of SharePoint 2013 on a Windows 2008 R2 system you will see that the New Web Application button is in central administration is disabled even when you have logged in as system account.

The fix for enabling the new web application button is to turn off the notification settings for the system account in the windows server. Below are the steps for turning off notification
1.Open System and security in control panel
2.Under Action center click "Change user account control settings".
3.Move the scroll bar to never notify and click Ok.
4.Restart the server.

After the system has restarted and you navigate to the create web application screen you will now see that the new web application button will be enabled.