This does effectively work.
In order to use the nitrokey in mailboxorg you have to:
a) log into the webinterface, go to settings
b) use otp as menu point
c) input the PIN, select “yubi or different generators”
d) select: webinterface all other password
e) you generate now the key in the nitrokey pro, hexadecimal, 8 bit 30 sec (gives 80 digits).
f) you cancel by hand everything behind the 64th digit.
g) you copy via the app button the seed as hexadecimal to the pastebin
h) you paste the seed into the webinterface point of mailboxorg (having selected totp
i) you click O.K, now you safe in the app and you empty the pastebin of the seed!
j) you activate the token with the button activate the token selecting the token you did paste.
k) you finish your action with: activate OTP (send request).
L) you log out. To log in you have to:
put in you main mail address. Put in the PIN followed without space the number totp generated by that nitrokey. Return, you are in.
Verified! This was the only method that really worked with me.
Thank you so much to all who helped.
