SharePoint: Web part SPUserCodeNoAvailableServersFoundException error

Problem

Web part is not loading, you see exception SPUserCodeNoAvailableServersFoundException.

Solution

Start “Microsoft SharePoint Foundation Sandboxed Code Service”.

1. Go to Central Admin
2. Go to System Settings –> Manage services in this farm
3. At “Microsoft SharePoint Foundation Sandboxed Code Service” click “Enable Auto Provisioning”