I have had this issue for a long time now. It started around end of January when no matter how many attempts of uploading files (even smaller ones in size) 90% the responses ends up with “It seems that the file is no longer accessible”
I’m also confused for how long it has been going, I would assume it being quite a significant bug and couldn’t think it has anything to do w subscriptions as I’m sure the 20€/month includes file uploading and reading.