[mosquitto-dev] Mosquitto with two interfaces

[informatique <informatique@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Hello,

i try using mosquitto on a raspberry PI with Raspbian BUSTER

I have two interfaces the first on cable network (eth0) with an IP 
adresse 192.168.1.15. All work's fine with only this address.

And i have a second interface wlan0 with address 192.168.50.15

I have create a file RPI.conf in the subdirectory /etc/mosquitto.conf.d 
with

bind_interface wlan0

And a this point mosquitto doesn't start, if i  delete this file all is OK.

What can i do

Thank's for your help.

--
François-Marie