Landing page error due to lack of record visibility (sharing)
An error message, "Sorry, an error occurred," will appear on the landing page, and the survey will not be recorded in Salesforce.
If you have organization-wide sharing defaults of Private, you can grant access to Simple Survey one of two ways.
The easiest way to accomplish this, and grant full access to Simple Survey, is to bypass sharing and security by checking this option under Optional Setup in the Simple Survey Setup Wizard.
The second way is to define sharing rules that gives the Simple Survey Site Guest User access to records it does not own.
To do this set up a public group for Simple Survey Site Guest User and add read-only sharing rules to the three required objects and any other object linked to the Survey object (if the sharing model for that particular object is set to private).
First, create a public group:
Repeat Sharing Rules steps for Contact and Case Objects if they are set to Private as well as any other custom object linked to the Survey object which is also currently set to private for sharing.