Synology Drive on Mobile device not downloading files

Hi There!
I have synology drive app installed on my iPhone running ios 17.4.1.
The sync to my NAS works fine, I can see the files and photos etc that I want to, however when I want to download or export a file from my Drive to my phone I get an error report “Error unsupported URL” it gives me no further explanation…
Has anyone encountered this before?
Is it something I have missed in the initial setup perhaps?

Note this happens when I am on my home network, and when I am remote…

Any help will be appreciated!
Thank you