And then confirm sending signed message via the Ledger Nano S button?
Yeah... it'll prompt you on the Ledger Nano S to "confirm" that the message
hash is the same as the one displayed on the Electrum dialog.
Once you do that, it display the Message Signature in Electrum and then you can copy/paste the Message, Address and Signature from there and put it into a post here... You should also put a note saying it was created in Electrum (so people know that trying to verify using the websites won't work).
The standard format is:
-----BEGIN BITCOIN SIGNED MESSAGE-----
[YOUR_MESSAGE_GOES_HERE]
-----BEGIN SIGNATURE-----
[YOUR_ADDRESS_GOES_HERE]
[YOUR_SIGNATURE_GOES_HERE]
-----END BITCOIN SIGNED MESSAGE-----
Example from earlier in this thread:
-----BEGIN BITCOIN SIGNED MESSAGE-----
This id my Bitcointalk accaunt! My! 24/04/2019
-----BEGIN SIGNATURE-----
1MikadoVmK6BtotcwM7SP1trcWeWPkMhAa
HPSStSRZhQwFDm0S8lT1SWDt4HLKzA9xSHKSM4n6QIIELO6T8uoChWEIt+4HcgrIpfsW+j7oUCHhF7M6F8nf2e4=
-----END BITCOIN SIGNED MESSAGE-----