Getting "An unknown error has ocurred (1031)" when calling api.Sql2005CreateBackupAsync

Hello,

I have an application that uses the Control Panel API to backup a database three times a week, it worked fine for the last couple of months, until yesterday that I am getting the following error message in the event handler function (BackupCompleted):

"An unknown error has occurred (1031)".

I am using the following code to request a backup (I double checked that the Api Key and dbname are correct):

{
...
api.Sql2005CreateBackupCompleted += new dasp.discountasp.api.Sql2005CreateBackupCompletedEventHandler(BackupCompleted);
string dbName = ConfigurationManager.AppSettings["DatabaseName"];
LogString("Backup DB: " + dbName);
api.Sql2005CreateBackupAsync(ConfigurationManager.AppSettings["ApiKey"], dbName);
...
}

public static void BackupCompleted(object sender, AsyncCompletedEventArgs e)
{
if (e.Error == null)
{
...
}
else
{
LogString(e.Error.Message);
}
}


Any help will be appreciated.

Thank you,

MikeP.