a user reports problems to access hkps://pgp.mailbox.org on windows 10.
The debugging shows:
DBG: ntbtls(2): got an alert message, type: [2:40]
Expected behaviour: The keyserver connection is made to search for the pubkey.
This looks either like a software defect or a documentation deficit how to analyse
the problem to get a connection.
Observation: gpg 2.1.11 with gnutls on Debian contacts the keyserver just fine.
Has been tested with Gpg4win 3.0(rc) 3.0.0 beta 299.