OSWeb-Jatos: 'Failed to transfer data'
I am facing an issue in collecting online data. More than 30% of participants are receiving the following message at the end of the experiment: "Transferring your data, please wait a few moments.", after a long time the message "A problem occurred: Failed to transfer data" appears. Data are displayed in Jatos as "FAIL - Failed to transfer data." but, the data are there in full, without any missing trial. This is a problem for us because the participants are not redirected to the subsequent part of the study. Furthermore, I am worried about the fact that the process could potentially lead to an incomplete dataset in some cases.
One participant received a slightly different message at the end of exp ("JATOS isn't allowed to run a study with the study result ID 327.") but his results had the same FAIL label on Jatos.
I found a similar problem issued on this page but it was closed as it was solved with OSWeb 1.3.7 (I am using 1.3.11).
I would like to understand where the problem could lie.
When participants are running the experiment the Server uses a small % of its capacity. I am using a Digital Ocean server to host Jatos - Server specs: Droplet with 2 Dedicated vCPUs / 4 TB Transfer / 16 GB Memory / 25 GB Disk / LON1 - Docker 19.03.12 on Ubuntu 18.04.
188.8.131.52 OSWeb; OpenSesame 3.3.6; Python 3.7.6 | packaged by conda-forge | (default, Jan 7 2020, 21:48:41) [MSC v.1916 64 bit (AMD64)]; datamatrix 0.11.0; qdatamatrix 0.1.29; pseudorandom 0.2.2; fileinspector 1.0.2; QNotifications 2.0.6; QOpenScienceFramework 1.3.1; opencv 4.2.0; expyriment 0.10.0+opensesame2; IPython 7.12.0; numpy 1.18.1; scipy 1.3.1; PIL/ PILLOW [version unknown]; psychopy 2020.2.8; pygame 1.9.6; pygaze 0.7.2a2; pyglet 1.5.0; PyQt 5.12.3; serial 3.4; markdown 3.2.1; yaml 5.3.
Thank you for your help,