Hint to find 'Handlers' (HÃ¥ndtering) in the Danish Chrome browser:
I used some time to find out where to find the Chrome Handlers settings in the latest Danish Chrome version via the GUI is located on 'Sikkerhed og Privatliv' --> 'Indstillinger for websites' --> 'Yderligere tilladelser' ---> HÃ¥ndtering.
This location can also be directly by typing:
chrome://settings/handlers
From Handlers you can remove any incorrect settings and then mailto: work be setup as you want
There are lot of other articles how to do this :-)