not authorized error

I'm getting the following error all the time on all my devices.. anybody know a solution? 

Not authorized

Action: SyncAccount

OneSuite.Apps.Model.Exceptions.AccountAuthorizationException: Not authorized

  at XCalendarApp.CalDavProvider.DavBasicConnection.Request (System.Uri url, System.String httpMethod, System.String contentType, System.String requestContent, System.Collections.Generic.Dictionary`2[TKey,TValue] requestHeaders, System.Int32 maxRedirects) [0x0023b] in <e7a582c56e8a42fd893af782918beb41>:0 

  at XCalendarApp.CalDavProvider.DavBasicConnection.Request (System.Uri url, System.String method, System.String contentType, System.String requestContent, System.Collections.Generic.Dictionary`2[TKey,TValue] requestHeaders) [0x00081] in <e7a582c56e8a42fd893af782918beb41>:0 

  at Dav.Client.Common.DavCommon.Request (System.Uri url, System.String method, System.String contentType, System.String requestContent, System.Collections.Generic.Dictionary`2[TKey,TValue] headers) [0x00085] in <f292a3d5e9d64c65a49acb041f622d7d>:0 

  at Dav.Client.CalDav.CalDavServer.GetCurrentUserPrincipal () [0x0009e] in <f292a3d5e9d64c65a49acb041f622d7d>:0 

  at Dav.Client.CalDav.CalDavServer.completeUrl () [0x0006f] in <f292a3d5e9d64c65a49acb041f622d7d>:0 

  at Dav.Client.CalDav.CalDavServer.Create (System.Uri url, Dav.Client.Common.IConnection connection) [0x00101] in <f292a3d5e9d64c65a49acb041f622d7d>:0 

  at XCalendarApp.CalDavBaseProvider.CalDavBaseAccount`1[TCachedCalDavBaseCalendar].CreateCalDavServer (System.IServiceProvider scope, OneSuite.Apps.Model.Settings.AccountSecurityInfo accountSecurityInfo) [0x0007e] in <2cf67b0d195b414a986da3879373aaa0>:0 

  at XCalendarApp.CalDavBaseProvider.CalDavBaseAccount`1[TCachedCalDavBaseCalendar].CreateSyncScope (System.IServiceProvider scope) [0x000e4] in <2cf67b0d195b414a986da3879373aaa0>:0 

  at XCalendarApp.CalDavProvider.CalDavBasicConnectionBaseAccount`1[TCachedCalDavBaseCalendar].CreateSyncScope (System.IServiceProvider scope) [0x0007f] in <e7a582c56e8a42fd893af782918beb41>:0 

  at XCalendarApp.ProviderBase.AccountProviderBase`9[TCachedCalendar,TProviderCalendarItem,TCachedAppointment,TProviderAppointmentItem,TCachedContacts,TCachedContact,TProviderContactItem,TAppointmentDbData,TAccountOptions].SyncAccount (System.Threading.CancellationToken cancellationToken, XCalendarApp.Model.SyncParam syncParam) [0x000fb] in <a48c919b0a5d45ee9df16d7db13a34e0>:0