docker cannot verify (letsencrypt-)cert

[clockwork6666]

Hey there,

maybe im doing it wrong but maybe the mosquitto-container isnt able to use tls (other than v1?)

I installed eclipse-mosquitto:latest (1.6.7 i think) and am trying to get it to connect to an external broker via tls.

the container has /etc/ssl/certs from host via ro-mount.

container-bridge-config:
connection blubb
address somehost.de:8883
bridge_capath /tmp
remote_clientid clk-home
remote_username user
remote_password password
topic '#' in 2
start_type automatic
try_private true

external-bridge-log-message:
OpenSSL Error: error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca

container-log-message
OpenSSL Error: error:14007086:SSL routines:CONNECT_CR_CERT:certificate verify failed

halp please! :)