Mint 18.2 / KDE Connect - firewall and writing permission

     In order for KDE Connect to work, the appropriate ports in Mint firewall must be opened. The simplest way to do it is trough command line like this:

     sudo ufw allow 1714:1764/udp

     sudo ufw allow 1714:1764/tcp

     sudo ufw reload

  

     Another problem with KDE Connect was an error about writing to file  /home/neklar/.local/share/user-places.xbel

Solution:

1. open Dolphin as root (sudo dolphin) and go to specified folder

2. right-click on files, Properties

3. in Permission section give to "Others" permission to read and write

4. click OK