Carddav account to Synology-DS-CardDAV-Server through MyFritz dont run

Hello Community. I am using Jolla Sailfis OS2.0 (2.0.0.10(Saimaa)) and PC-Clients under Ubuntu-12.0.4 lts. I use caldav-calendars with thunderbird lightning hosted by my own Synology-Server under https://ip:port/sync/user/ from LAN with static ip, from www with connection through „Myfritz“ from any Clients und with my Jolla - all with regular funktion. Under „Myfritz“, the ip has the form of https://xxxxx.myfritz.net:port/sync/user And now i want to use carddav with the same mashines. the path : https://ip:port/addressbooks/users/user/addressbook runs from LAN with static ip, from www with connection through „Myfritz“ from any Clients but the Jolla opens under „carddav and caldav“ an account, the status is „active“, the Password is accepted and : . . . nothing works. Under "import contacts" the account dont appear and the existing contacts dont changes - what happens ? Please help