MindProbe server down: 502 Bad Gateway worldwide
Hello,
Since this evening (10 September 2026, CEST), the MindProbe JATOS server has been returning the following error:
502 Bad Gateway
nginx/1.18.0 (Ubuntu)
I cannot access the MindProbe server in any browser. I checked jatos.mindprobe.eu using a website availability service with servers in multiple countries, and it returned the same 502 error from every location. Therefore, this seems to be a server-side outage affecting the entire MindProbe JATOS service.
Unfortunately, I had just launched a study and was about to begin active data collection, so I have had to pause recruitment.
Does anyone know:
- whether this outage is already known or related to maintenance;
- whether a similar MindProbe outage has happened before;
- how long these outages usually take to resolve;
- and whether researchers need to take any action after the server becomes available again?
Any information or help would be greatly appreciated, as the outage is currently delaying active data collection.
Thank you!
Comments
Hi,
I'm currently investigating the reasons for this server downtime.
Best,
Kristian
Mindprobe is up again. Sorry, if the downtime caused any inconveniences.
K.
Thank you so much!
Hello, JATOS has encountered the problem of 502 bad gateway again now.
I'll look into it
Yes, same problem here with the 502 bad gateway right now.
Mindprobe is up again.
Both incidents were causes by a sudden overloading of JATOS and a subsequent crash.
Hi all,
My participants are experiencing the same issue. I've also paused recruitment and have deleted as many experiments/data I had on my account as I could, in case that was the issue. I know this is a tricky question, but when would it be "safe" to launch studies again? Thank you for all the work!
Hi, I’m Kristian, the administrator of MindProbe. I wrote this with the help of AI (sorry it's late).
Both incidents were caused by sudden spikes in study runs originating from Prolific. We had not experienced this kind of load before. We have spoken with the researcher involved, who has agreed to take additional precautions in the future.
We are currently considering ways to prevent similar incidents—for example, introducing quotas limiting the number of study runs per user or study within a given period.
As you know, MindProbe is provided free of charge, and we would like to keep it that way. Consequently, we cannot offer an uptime guarantee. That said, MindProbe has generally been very reliable, and maintaining that reliability is important to us. We are investigating what changes we can make, but unfortunately cannot guarantee that similar incidents will never happen again.
Best,
Kristian
Hi Kristian,
I am just writing a message to report the same issue, as of september 18th, 5:16 PM CEST.
Thank you for your work on maintaining MindProbe, I hope these problems are not too serious.
Hi Kris, I have received the same problem,
I have a fair amount of studies on mindprobe but will be able to start erasing them when I finally finish data collection in a few days/a week, it has been an invaluable resource!
Yes, unfortunately MindProbe/JATOS crashed again due to high load. We are investigating the reasons. Until then Mindprobe is apparently not reliable. I restarted it again.