Cannot enter sources

I am writing my conclusive rapport for a course and cannot enter sources in my reference list.
I can put the cursor in the input fields but I cannot write anything. It is as if the keyboard is dead - but it Works fine everywhere else.

I want to use the Harvard system (mandatory) and want to enter the url https://icd.who.int/browse10/2016/en#/F78

into the reference list.

How do I fix this?
See screenshot.

I have called MS Denmark but they told me to ask here instead.

Windows 10, MS Surface pro 6 with pen and keyboard.