Transmission app says storage is full but it's not!

Hi, I have a problem with this device. I am trying to download using Transmission. It says that the storage is full. However, I have more than 4 TB free. I don’t know what’s going on.

I see that others have had this problem but I cannot see what the answer is. Any help would be greatly appreciated. Thanks!

Edit: Looks like I categorized this wrong. I am running the latest firmware OS 5. Computer i’m using to connect is running linux / windows 11.