I encounter problems when synching changed contacts from Android phone (Android 6.0) to Posteo. Synching the contacts from Posteo to android worked but when I make changes to the contacts on the phone I get errors, that I cannot troubleshoot.
It seems the posteo Server has an error with the transmitted vcard, but I don’t see a reason for this.
I tried another carddav sync software that doesn’t have the problem, but wanted to stick wiht DavDroid.
Any help would be appreciated,