Config:

{
  "logins": [
    {
      "username": "admin",
      "password": "Pass123"
    }
  ],
  "anonymous": false,
  "customize": {
    "active": false,
    "folder": "mosquitto"
  },
  "certfile": "fullchain.pem",
  "keyfile": "privkey.pem",
  "require_certificate": false
}



Log
1573758744: Socket error on client AFE-Stacja, disconnecting.
1573758745: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573758746: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573759459: Client mqtt-explorer-0259b122 disconnected.
1573759493: Saving in-memory database to /data/mosquitto.db.
1573760038: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573760039: Client AFE-Stacja already connected, closing old connection.
1573760039: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573760723: Socket error on client AFE-Stacja, disconnecting.
1573760724: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573760725: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573761294: Saving in-memory database to /data/mosquitto.db.
1573763095: Saving in-memory database to /data/mosquitto.db.
1573764896: Saving in-memory database to /data/mosquitto.db.
1573765530: Client AFE-Stacja has exceeded timeout, disconnecting.
1573765538: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573765540: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573766150: Client AFE-Stacja has exceeded timeout, disconnecting.
1573766164: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573766165: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573766697: Saving in-memory database to /data/mosquitto.db.
1573766824: Client AFE-Stacja has exceeded timeout, disconnecting.
1573767105: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573767107: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573768498: Saving in-memory database to /data/mosquitto.db.
1573770299: Saving in-memory database to /data/mosquitto.db.
1573771223: Client AFE-Stacja has exceeded timeout, disconnecting.
1573772100: Saving in-memory database to /data/mosquitto.db.
1573773901: Saving in-memory database to /data/mosquitto.db.
1573775702: Saving in-memory database to /data/mosquitto.db.
1573777503: Saving in-memory database to /data/mosquitto.db.
1573779304: Saving in-memory database to /data/mosquitto.db.
1573781105: Saving in-memory database to /data/mosquitto.db.
1573782906: Saving in-memory database to /data/mosquitto.db.
1573784707: Saving in-memory database to /data/mosquitto.db.
1573786508: Saving in-memory database to /data/mosquitto.db.
1573788309: Saving in-memory database to /data/mosquitto.db.
1573790110: Saving in-memory database to /data/mosquitto.db.
1573791911: Saving in-memory database to /data/mosquitto.db.
1573793196: Socket error on client auto-55214144-7DA1-4437-553F-2022742748F7, disconnecting.
1573793222: New connection from 172.30.32.1 on port 1883.
[INFO] found homeassistant on local database
1573793224: New client connected from 172.30.32.1 as auto-D49413F6-C4FF-C4AC-4BC6-1BF5D29379EE (p2, c1, k60, u'homeassistant').
1573793712: Saving in-memory database to /data/mosquitto.db.
1573794067: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573794068: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573795513: Saving in-memory database to /data/mosquitto.db.
1573797314: Saving in-memory database to /data/mosquitto.db.
1573799115: Saving in-memory database to /data/mosquitto.db.
1573800916: Saving in-memory database to /data/mosquitto.db.
1573802292: Client auto-D49413F6-C4FF-C4AC-4BC6-1BF5D29379EE disconnected.
1573802319: New connection from 172.30.32.1 on port 1883.
[INFO] found homeassistant on local database
1573802320: New client connected from 172.30.32.1 as auto-5E4E8BB8-6F8C-8DEB-4ABD-98323F1C21A4 (p2, c1, k60, u'homeassistant').
1573802702: Client AFE-Stacja has exceeded timeout, disconnecting.
1573802716: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573802717: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573802717: Saving in-memory database to /data/mosquitto.db.
1573802957: Client AFE-Stacja has exceeded timeout, disconnecting.
1573802960: New connection from 192.168.1.23 on port 1883.
1573802960: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573803415: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573803416: Client AFE-Stacja already connected, closing old connection.
1573803416: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573803632: Client auto-5E4E8BB8-6F8C-8DEB-4ABD-98323F1C21A4 disconnected.
1573803659: New connection from 172.30.32.1 on port 1883.
[INFO] found homeassistant on local database
1573803660: New client connected from 172.30.32.1 as auto-24568F2F-E2CC-2D3C-3197-E685096B7610 (p2, c1, k60, u'homeassistant').
1573804203: Socket error on client AFE-Stacja, disconnecting.
1573804207: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573804208: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573804518: Saving in-memory database to /data/mosquitto.db.
1573806319: Saving in-memory database to /data/mosquitto.db.
1573806798: Client AFE-Stacja has exceeded timeout, disconnecting.
1573808120: Saving in-memory database to /data/mosquitto.db.
1573809921: Saving in-memory database to /data/mosquitto.db.
1573811722: Saving in-memory database to /data/mosquitto.db.
1573813523: Saving in-memory database to /data/mosquitto.db.
1573815324: Saving in-memory database to /data/mosquitto.db.
1573817125: Saving in-memory database to /data/mosquitto.db.
1573818926: Saving in-memory database to /data/mosquitto.db.
1573820727: Saving in-memory database to /data/mosquitto.db.
1573822528: Saving in-memory database to /data/mosquitto.db.
1573824329: Saving in-memory database to /data/mosquitto.db.
1573826130: Saving in-memory database to /data/mosquitto.db.
1573827931: Saving in-memory database to /data/mosquitto.db.
1573829732: Saving in-memory database to /data/mosquitto.db.
1573830699: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573830700: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').

Anonymus set to fulse
After restart

Log
[16:27:44] INFO: Setup mosquitto configuration
[16:27:44] WARNING: SSL not enabled - No valid certs found!
[16:27:44] INFO: Found local users inside config
[16:27:44] INFO: Initialize Hass.io Add-on services
[16:27:44] INFO: Initialize Home Assistant discovery
[16:27:44] INFO: Start Mosquitto daemon
1573831664: mosquitto version 1.6.3 starting
1573831664: Config loaded from /etc/mosquitto.conf.
1573831664: Loading plugin: /usr/share/mosquitto/auth-plug.so
1573831664: |-- *** auth-plug: startup
1573831664:  ├── Username/password checking enabled.
1573831664:  ├── TLS-PSK checking enabled.
1573831664:  └── Extended authentication not enabled.
1573831664: Opening ipv4 listen socket on port 1883.
1573831664: Opening ipv6 listen socket on port 1883.
1573831664: Opening websockets listen socket on port 1884.
1573831665: Warning: Mosquitto should not be run as root/administrator.
1573831665: New connection from 172.30.32.1 on port 1883.
1573831665: Socket error on client <unknown>, disconnecting.
1573831665: New connection from 172.30.32.1 on port 1883.
[INFO] found homeassistant on local database
1573831667: New client connected from 172.30.32.1 as auto-990ACC18-46CB-E7E7-DBE7-7FD4011DFD70 (p2, c1, k60, u'homeassistant').
1573831667: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573831668: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').
1573832260: Socket error on client AFE-Stacja, disconnecting.
1573832265: New connection from 192.168.1.23 on port 1883.
[INFO] found admin on local database
1573832266: New client connected from 192.168.1.23 as AFE-Stacja (p2, c1, k15, u'admin').