Several of our developers have been unable to upload thumbnails on any of our games. They’ve tried clearing cookies, changing accounts and restarting PC.
This has been occurring for 3 days.
Affected user (in case you team needs it to test): is2belli
Video of the issue:
Video of user uploading thumbnail on another game not owned by us:
Hello there,
Try having the group’s owner upload the thumbnails & see if the issue still persists!
if it solves the problem, then I believe it is a recently added feature Roblox added to ensure there’s a security measure in place, so that members (including developers) cannot modify anything group related incase they went “rogue”
However I have not found anything to support this claim
it is still merely a speculation.
Have the thumbnails been moderated before?
no
I can upload but that’s not a solution for the problem
You are 100% correct! it wasn’t a solution to the problem
Upon further investigation and personally testing again myself, it seems the technicalities you were facing was indeed a bug! and it appears to have been fixed, tell your developing team to retry again the problem should no longer resurface.
Although this post was made well over 5 months ago, it’s probably a complication that happened on their end temporarily, with all the new integrations they have been implementing within the system.
Don’t hesitate to share the results! hopefully I was enough help 
Hi @LuaBearyGood,
Thanks so much for the report! Could you help me understand which permissions the affected users have? If they have Edit all group experiences permission, please update their role to include Edit & publish all group experiences if you’d like them to upload thumbnails.
We are working on providing creators more and more fine grained control over what permissions can be provided to which group members. One such new permission is Edit & publish all group experiences . This permissions would allow users to edit and publish games, but also upload new thumbnails and update game settings. The permission Edit all group experiences will, going forward, no longer allow users to publish experiences or thumbnails.
On our side, I do see from your video that the error message displayed on failure to update the thumbnail is vague, and we’ll working on updating that text to make it clearer for users they do not have the correct permissions for that action. Let me know if you have any other questions!