Hello,

Our site which has been running fine for 6+ months is currently offline - all pages are returning a white screen and 200 status code.

I can login to Umbraco but can't view/edit any content - with an error like

Server error: Contact administrator, see log for full details.
Failed to retrieve data for content id xxxx

Checking the error logs shows:

2016-05-19 15:20:54,021 [12] ERROR Umbraco.Web.Scheduling.ScheduledPublishing - [T42/D4] An error occurred with the scheduled publishing. The base url used in the request was: http://www.example.com:80/umbraco/, see http://our.umbraco.org/documentation/Using-Umbraco/Config-files/umbracoSettings/#ScheduledTasks documentation for details on setting a baseUrl if this is in error
System.Net.WebException: The remote server returned an error: (400) Bad Request.
   at System.Net.WebClient.UploadDataInternal(Uri address, String method, Byte[] data, WebRequest& request)
   at System.Net.WebClient.UploadString(Uri address, String method, String data)
   at System.Net.WebClient.UploadString(String address, String data)
   at Umbraco.Web.Scheduling.ScheduledPublishing.PerformRun()

There's no scheduled tasks in the Umrbaco settings file and I've restarted the site's application pool - any ideas, please!