Blank screen and no Thank You page after form submission

Submission appears in the database, but no Thank You screen or notification e-mails. Stopped working a few weeks ago. I checked the forum, but none of those fixes worked. Clone of the form works, but I need to keep all previous submissions together with new ones, and do not want to change the link to my form.

Here is the link to the original form: http://form.jotformpro.com/form/40677869645978

and the clone of that form is here: http://form.jotformpro.com/form/50937647278974

I found out that the difference between the two forms is that the clone did not include include integration to Google docs. Something in my Google Doc spreadsheet wasn't working. I removed the integration and the original form now works.

I could not find a way to make the integration work, and noticed that other users are also having problems. I can do without this feature until your programmers get it working, though. Thanks for your help.