There is an app into nexcloud to connect a samba/cifs sharing.
Did you install on RPI?
First of all thanks to you quick reply.
And it seems to me that I'm an idiot or getting old or both...
I checked again every step of how to mount the smb shares. And it turned out that I always referenced to the absolute path instead of the shared folder. Anyway it is working now. Sorry if I bothered you all.