Error uploading participants' response

URL of experiment:

Description of the problem: Participants’ data is not uploading
At the end of my experiment I received the following message. When I looked for the data, as expected, I was not able to find it.

Unfortunately we encountered the following error:

when uploading participant's results for experiment: MRLab/efmath_kids_decimals_arith_spinners_sym_spin

Try to run the experiment again. If the error persists, contact the experiment designer.

I wonder if you’ve reached a maximum character length for the experiment name.

When I look at the console I also got these messages.
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at (Reason: CORS request did not succeed).

error: core-2020.2.js:281:15

Object { origin: “ServerManager.uploadData”, context: “when uploading participant’s results for experiment: MRLab/efmath_kids_decimals_arith_spinners_sym_spin”, error: “” }


FATAL unknown | {“origin”:“ServerManager.uploadData”,“context”:“when uploading participant’s results for experiment: MRLab/efmath_kids_decimals_arith_spinners_sym_spin”,“error”:""}

Interestingly enough, it only happens in Firefox and only at the very end of the task. If I press ESC, data is correctly saved.

I just noticed that your URL is of an odd form. Try one of the form

Thank you for posting additional information about this issue- I just received the same error for one of my participants, but I don’t have access to any additional information. Do you remember what the cause of the error was?

My task has successfully run for more than 80 other participants, so it is possible that this is a one time glitch or related to internet dropout.