It works! Again, thank you very much for your help. I am also inspired by this tutorial
https://we.riseup.net/debian/using-the- ... th-subkeys .
Step 7 was very important for me because I never did a "key 1".
Quote:
7. move the encryption key above to the card:
$ gpg --edit-key $KEYID
Command> toggle [this sets you into secret key mode]
Command> key $NUMBER [select the encryption key above, it'll be the last one if you just generated it, and this command puts a * next to it]
Command> keytocard
Please select where to store the key:
(2) Encryption key
Your selection? 2
Command> save