This error may occur when the Web TimeSheet URL specified in the integration manager is incorrect. Please refer the attachment for the error message (QuickBooks Integration.jpg).

Resolution:
While integrating Replicon hosted Web TimeSheet with QuickBooks using the Integration module, when prompted for 'Web TimeSheet URL', ensure that the URL is entered as https://na1.replicon.com company key
Here Company Key, is the Company Name that is used on the Web TimeSheet login page. (https://login.replicon.com)
If secure browsing is enabled in Web TimeSheet, then the URL would be
https://na1.replicon.com company key