Desktop created vault on OneDrive is empty on mobile

On the desktop I created a vault on my OneDrive (Win 10) and placed two files in it; these are viewable on desktop once vault is opened. I added the same vault on my IOS phone and gave Cryptomator access to my OneDrive account. When I open this vault it shows as empty; the two file are not there. What am I missing?

Just to be sure: the OneDrive sync was completed? You can see encrypted folders with encrypted files in a „d“ directory when you open the vault folder in onedrive with a browser?

Yes, the folder directory is intact with the _d directory; when opened in the IOS there is nothing there as far as the encrypted files are concerned; I created a vault on Drop Box with the IOS phone; and put files in there with Win 10 desktop and the phone displayed the files. I use OneDrive as a last resort for important content; not a big fan. I give up and use Drop Box for only two special small files I need encrypted and for free. As with many of the OneDrive problems I see in your community,
I am staying away from OneDrive.

That’s wrong. The directory should be named d, not _d.

PS: I use OneDrive for years now without any problems.