Because I had some problems getting it to work on Windows here is the final Solution.
Test how good you SSL Setup is with ssllabs.
Can't Start
----
ECDHE-RSA-AES128-GCM-SHA256
ECDHE-RSA-AES256-GCM-SHA384
AES128-GCM-SHA256
AES256-GCM-SHA384
AES128-GCM-SHA384
ERR_SSL_VERSION_OR_CIPHER_MISMATCH
----
ECDHE-RSA-AES128-SHA256
ECDHE-RSA-AES256-SHA384
AES128-SHA256
AES256-SHA256
WORKS
----
ECDHE-RSA-AES128-SHA
ECDHE-RSA-AES256-SHA
AES128-SHA
AES256-SHA
ciphers = undefined // sslabs grade "C", better use the 4 woking above to get grade "A-"
[chttpd]
bind_address = 0.0.0.0
[daemons]
httpsd = {chttpd, start_link, [https]}
[ssl]
cert_file = C:/letsencrypt/etc/live/tools.amanninformatik.ch/cert.pem
key_file = C:/letsencrypt/etc/live/tools.amanninformatik.ch/privkey.pem
cacert_file = C:/letsencrypt/etc/live/tools.amanninformatik.ch/fullchain.pem
secure_renegotiate = true
ciphers = ["ECDHE-RSA-AES128-SHA", "ECDHE-RSA-AES256-SHA", "AES128-SHA", "AES256-SHA"]
tls_versions = [tlsv1, 'tlsv1.1', 'tlsv1.2']