error message in Zoho creator from a link to form on our google site

error message in Zoho creator from a link to form on our google site

The user fills in all of his/her data and clicks on 'submit'. Once that happens this error message pops up 'Error occurred please contact application owner'.  The link to the form is on a google site.

The error happens from time to time and is inconsistent in the circumstances.  I will get one or two calls and then nothing  and then a couple of months will go by and it will happen again.  It is usually  accessing using a phone (android and iphone).  Can't pinpoint the issue.