Hello michimine,
The conversations system on the appeals site is no longer in use, which is why it keeps displaying "Please wait". You can ignore this since this status message won't change anymore.
As of now, there's a different way of rediscussing your Sentinel ban. You can send an e-mail to
sentinelteam@cubecraft.net along with your username and a new appeal if you would like to rediscuss your Sentinel ban. Hope this helps and don't hesitate to ask away if you have any further questions.
Thanks for reaching out and have a nice rest of your day,