Errors connecting to SharePoint Online

[kdkendall]

Have recently started receiving the below errors in an application that connects to SharePoint Online.

Nothing has changed in the application. Has anything changed in SharePoint Online?

For security reasons DTD is prohibited in this XML document. To enable DTD processing set the DtdProcessing property on XmlReaderSettings to Parse and pass the settings into XmlReader.Create method.

System.Xml.XmlException: 'center' is an unexpected token. The expected token is '"' or '''. Line 7, position 12.

[#2]

This can be caused by your ISP Virgin Media. Check http://pryankrohilla.blogspot.com/2014/05/error-resolved-connect-sposervice-for.html on how to resolve.

[#3]

Thanks, but we don't use that ISP.

Its is also happening at 2 different sites that use different ISP's.