I struggled alot with this (Cannot create a test file under directory /mnt/remote-storage) .. the solution that worked for me for a synology is : Go to control Panel -> File Services -> Advanced -> Enable bypass traverse checking !I hope this helps s...

Finally i found the solution ..so annoying .  Go to control Panel -> File Services -> Advanced -> Enable bypass traverse checking !I hope this helps someone .

I have the exact same problem and pretty similar config , were you able to find a solution ?