Symptoms:
The following error occurs when connecting to Web TimeSheet using the QuickBooks Integration Manager,
 
"Could not connect to Web TimeSheet, System Invalid Operation. Exception:There is an error in XML document".
 
Resolution:
Remove the main.aspx from the Web TimeSheet URL in QuickBooks Integration Manager. For example, a typical Web TimeSheet URL would like as follows,
 
https://hosted.webtimesheet.com/< company name >/main.aspx
 
The URL required on the QuickBooks Integration Manager is as follows,
 
https://hosted.webtimesheet.com/< company name >/
 
This is required as the .aspx pages are only for the web browsers and the client library doesn't require it for data transfer.