Just helped someone who was seeing a difference between the Preview mode and what Thingworx View was showing. The experience was being developed for public access, so what was happening is that Preview mode worked because they were using their Studio credentials to run the Thingworx service. When they used Thingworx View, they were using es-public-access to run the Thingworx service. And es-public-access did not have the runtime permissions to execute the service.
The error indication was found in the Application Log complaining about the Entity and Service not being able to be run.
Don't forget to set your permissions for es-public-access so it can run your services!