MacOS 10.11 SMB server

Hi,

I'm new to Ubuntu and linux and have just finished installing it on my laptop. Now I'm having trouble accessing shares on my OSX server (which worked while I was using windows).

I'm using Ubuntu Gnome 16.04 and I see my server in the network and if I try to access it I enter my useame on the server, the correct workgroup and the password, but then the password prompt comes up again.
If I use "Coect to server" -> "smb://xxx.xxx.xxx.xxx the same happens.
I checked that the samba client is installed on my laptop and I checked dmesg, but could not see any error message.

Would somebody be able to point me in the right direction?

Thanks.

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