Hi,
Attn:pedrodelafiesta, simonbsays
Here is how
it worked for me:
After all the settings in the Diskstation are done (according to the manual

), that is
The network connection is fine
WebDAV is on
privileges have been assigned
The ports5005, 5006, have been opened for the disk station
The firewall is also set to accept port 5005, 5006
The Mobile device has the DS File app
you should connect to the Diskstation
accordingly:
When you are connecting
from the local network (the access point, router where the Diskstation is located), use the local network connection option.
Do not use your IP (as seen from outside) because it will not work.
To be able to connect within your network using your IP, you'll have to use another access point (as long as they don't have the same Gateway) as the one the diskstation is using.
Or another Internet connection, e.g. from your carrier.
From the network ->> use the network option or IP + different Access point
From anywhere else ->> Use your ip