I have same problem, clients (mqttfx or java with paho) can not connect to mosquitto with same error if option acl_file is used. No problem with mosquitto 1.5.8-0mosquitto1~bion from ppa.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1815732 Title: mosquitto 1.4.15-2ubuntu0.18.04.1 "Socket error on client <unknown>, disconnecting." To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mosquitto/+bug/1815732/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs