Solution for Xmarks Cannot Sync or Connection Reset on Ubuntu Linux
Run in terminal
sudo gedit /etc/hostsEnter the following content in the editor that pops up:
#xmarks64.147.188.86 www.xmarks.com64.147.188.92 api.xmarks.com64.147.188.89 login.xmarks.com64.147.188.87 sync.xmarks.com64.147.188.86 static.xmarks.com64.147.188.86 download.xmarks.com64.147.188.86 my.xmarks.comAfter saving, open xmarks settings menu, select “Advanced”, choose “Encrypt All” in the encryption dropdown, and you can sync.