The survey doesn't contain visible elements

I’m guiding another cohort of around 100 3rd year students through using Pavlovia Survey for their final year project. I’d two workshops this morning the first of 35, second of 34.

In both some students (about 20%) encountered an issue that suggested their survey was not being saved to the server, it would appear fine in Design and Preview but then when they tried to run it they got an error screen saying ‘This survey does not contain any visible elements’. (see screenshot)

This happened with 8 in the first workshop and 5 in the second. If they logged into their account in a different browser they could see the survey but it was empty with no questions in it. The same thing happened inf they logged out and back in again

It happened across a range of browsers roughly in proportion to that used across the class.

Im having this same issue now: “The survey doesn’t contain visible elements”

Do you have a saving issue (you have to save before testing) or any logic which might hide questions?

It’s on occassional student laptops (maybe 1 or 2% out of a cohort of 150). There is logic (at the start, there’s a radio button for a consent form: if yes, continue and if no, end survey), but there’s no unusual saving mechanism.

The most likely explanation is that the students tried their surveys before saving them. I sometimes do this.