Hi,
I can't sync my addresses stored in a Synology Carddav-Server with KAddressbook on Opensuse Leap 15. KAddressbook does not fetch any Conacts from the Carddav resource.
Theres No problem with the IOS implementation and the Windows Application CaldavSynchronizer to sync Carddav and Caldav Resources with Outlook. So the carddav resource seems to work.
The ressource is available under the url https://<nas>:<port>/addressbooks/__uids__/<GUID>/addressbook/
The carddav Ressource is protected by username and password.


Here's an output of akonadiconsole:
akonadi_davgroupware_resource_2 (0x555eb787c890) 38 Command: FetchCollections collections: UID 107 resource:akonadi_davgroupware_resource_2 mimeTypes:() ancestorsAttributes:QSet() depth:0 ancestorsDepth:2 enabled:false syncPref:true displayPref:false indexPref:false fetchStats:false 
akonadi_davgroupware_resource_2 (0x555eb787c890) 38 Response: FetchCollections Error code: 0 Error msg: name: https://<nas>:<port>/addressbooks/__uids__/<GUID>/addressbook/ isVirtual: false referenced: false indexPref: Undefined syncPref: Undefined displayPref: Undefined enabled: true cachePolicy: localParts: (ALL) checkInterval: 5 cacheTimeout: -1 inherit: true syncOnDemand: false statistics: Response: FetchCollectionStats Error code: 0 Error msg: count: 0 unseen: 0 size: 0 id: 107 parentId: 101 mimeTypes: (text/directory, inode/directory) remoteId: https://<nas>:<port>/addressbooks/__uids__/<GUID>/addressbook/ remoteRevision: resource: akonadi_davgroupware_resource_2 searchQuery: searchCollections: QVector() ancestors: QVector(id:101 remoteId:akonadi_davgroupware_resource_2 name:akonadi_davgroupware_resource_2 attributes:QMap() , id:0 remoteId: name: attributes:QMap() ) attributes: QMap((AccessRights, a)(davprotocol, 1)) 
akonadi_davgroupware_resource_2 (0x555eb787c890) 38 Response: FetchCollections Error code: 0 Error msg: name: isVirtual: false referenced: false indexPref: Undefined syncPref: Undefined displayPref: Undefined enabled: true cachePolicy: localParts: () checkInterval: -1 cacheTimeout: -1 inherit: true syncOnDemand: false statistics: Response: FetchCollectionStats Error code: 0 Error msg: count: 0 unseen: 0 size: 0 id: -1 parentId: -1 mimeTypes: () remoteId: remoteRevision: resource: searchQuery: searchCollections: QVector() ancestors: QVector() attributes: QMap() 
akonadi_davgroupware_resource_2 (0x555eb787c890) 39 Command: FetchCollections collections: UID 107 resource: mimeTypes:() ancestorsAttributes:QSet() depth:0 ancestorsDepth:2 enabled:true syncPref:false displayPref:false indexPref:false fetchStats:false 
akonadi_davgroupware_resource_2 (0x555eb787c890) 39 Response: FetchCollections Error code: 0 Error msg: name: https://<nas>:<port>/addressbooks/__uids__/<GUID>/addressbook/ isVirtual: false referenced: false indexPref: Undefined syncPref: Undefined displayPref: Undefined enabled: true cachePolicy: localParts: (ALL) checkInterval: 5 cacheTimeout: -1 inherit: true syncOnDemand: false statistics: Response: FetchCollectionStats Error code: 0 Error msg: count: 0 unseen: 0 size: 0 id: 107 parentId: 101 mimeTypes: (text/directory, inode/directory) remoteId: https://<nas>:<port>/addressbooks/__uids__/<GUID>/addressbook/ remoteRevision: resource: akonadi_davgroupware_resource_2 searchQuery: searchCollections: QVector() ancestors: QVector(id:101 remoteId:akonadi_davgroupware_resource_2 name:akonadi_davgroupware_resource_2 attributes:QMap() , id:0 remoteId: name: attributes:QMap() ) attributes: QMap((AccessRights, a)(davprotocol, 1)) 
akonadi_davgroupware_resource_2 (0x555eb787c890) 39 Response: FetchCollections Error code: 0 Error msg: name: isVirtual: false referenced: false indexPref: Undefined syncPref: Undefined displayPref: Undefined enabled: true cachePolicy: localParts: () checkInterval: -1 cacheTimeout: -1 inherit: true syncOnDemand: false statistics: Response: FetchCollectionStats Error code: 0 Error msg: count: 0 unseen: 0 size: 0 id: -1 parentId: -1 mimeTypes: () remoteId: remoteRevision: resource: searchQuery: searchCollections: QVector() ancestors: QVector() attributes: QMap()