SharePoint 2013 App domain for this site has already been assigned

When deploying a SharePoint 2013 add-in (or app) from Visual Studio, we may get the following error:

ErrorDetail: The content database on the server is temporarily unavailable ErrorType: Transient ErrorTypeName: Intermittent ExceptionMessage: The App domain for this site has already been assigned

This error is usually a result of an add-in prefix update on the farm.  When we configure the on-premises development environment for SharePoint add-ins, we need to provide a prefix to our apps. This prefix is used as a subdomain name for the app.

Domain	Description
ozkary.com	Domain name
app.ozkary.com	App subdomain name. app is the add-in prefix that was configured on the farm.

Set up SharePoint on premise development environment

https://msdn.microsoft.com/en-us/library/fp179923(v=office.15).aspx

Solution

To solve this problem, we need to make sure that the service returning this error is re-started after making the prefix change. If we are sure that our prefix is correct (see the URL on the browser when loading a different app from SharePoint), we just need to restart the service. Otherwise, run the command (PowerShell) to update the prefix and re-start the service as shown in the next steps:

Update the add-in prefix

This is the command to update the add-in prefix (SharePoint Management Shell). Notice the word “app”. This is the prefix.

Set-SPAppSiteSubscriptionName -Name "app" -Confirm:$false

Re-Start the service

These are the commands to re-start the service (stop/start). Run this command from the windows command shell (use Run as Administrator).

net stop sptimerv4 net start sptimerv4

Provided that there are no errors, we should be able to go back to Visual Studio and deploy the app.

Originally published by ozkary.com