Backup to Nabu Casa fails?

I set up the new scheduled backup, it works fine locally and to my NAS but fails to Nabu Casa? Isn’t it ready for NC?
I have Adguard DNS set up, but I’m not sure if that could affect anything, I can’t see anything relevant in the logs for it.
I got it updated to 2025.1.2 as I saw there were some time out adjustments, but that didn’t help.
My backups are just under 6 GB.