Jumping on this, we posted over on ask.vrc, only thought about checking feedback.vrc and found the same post. If you still need logs I'm happy to send them. I've tried with a vpn, I've tried regenerating id's, tried logging out and back in, I can upload the world, edit the description but if I try to upload a new thumbnail I get, "File already uploaded, 500 internal error, application error" I've found that the images are uploading because when I use vrcx I have them as an option to pick from but it won't change the thumbnail even with that. https://ask.vrchat.com/t/i-get-an-application-error-whenever-i-try-to-update-the-thumbnail-for-my-world/44249/4

Hi! Thanks for the report.

I will need a little more details before I can investigate this.

First of all - it is always good to check if its just an issue with accessing Amazon Web Services (the storage for the thumbnails).

Easy way to do that is to get some kind of VPN, e.g. cloudflare warp: https://one.one.one.one and see if you can upload with that enabled.

Then, if it is still an issue - I will need some logs.

To gather logs required - you will need to go to the settings tab of your SDK and check "Enable API Logs" checkbox before re-trying the upload.

Then try to upload the thumbnail as you were doing before.

Once you get into the error state - you can collect the logs from the "%LocalAppdata%\Unity\Editor" folder (just paste that text, without the quotes into your explorer address bar) and send the Editor.log file to orels@vrchat.com (please do not post the log file on the canny as it can contain some private information).

Thank you!