Trouble uploading Seedvault backup to cloud

(Sure would be nice if I could post this on GrapheneOS's unofficial sublem, but anyway . . . )

Using Graphene, I made a local Seedvault backup on my phone that I would like to upload to the cloud, specifically with/to Filen, but I can't seem to do this, and I'm not aware of any of my other files having this issue. Is this a permissions issue with Seedvault, or is there something else going on?