It’s me who’s responsible… I took 2! 
hello
I’m responding with a bit of delay
I didn’t do anything special for the Zigbee key, it was detected first time, but while searching on the net I saw that you shouldn’t put the key directly in the raspi but to move it away because of interference.
That’s what I did with a 3m extension. Also received today an antenna given for a 10db gain tested just 1 hour ago, I actually gained double in terms of reception, but after a few minutes it drops back and I’m still around 50 60 points, I say points because I don’t know what that corresponds to.
Well I still have a doubt about the antenna I will pass it through the VNA (vector network analyzer) I am a radio amateur LOL
well Zigbee is good but not very stable for radio, many factors come into play at these frequencies, walls, electrical and or radio wifi interference nearby and even weather.
you have to find the right location for the dongle and multiply the relays if you can.
for long distance the 445 uhf and 868 would certainly work better
The best might be to put the pi in a metal case and plug the key as close as possible! 
No scan button either 
Is your instance up to date?
Same issue with a configured dongle and new devices, there’s a problem.
(I’m migrating my Philips Hue bulbs to zigbee2mqtt)
Not everything is normal with your containers.
This is not an issue for me, but I understand pascal_sapin question in post 31 better.
On the contrary, there is absolutely the possibility of having several on the same network when there is a large number of objects on the network. When an object subscribes to another object, it specifies the address of the server to which it subscribes, and if the object to which it is subscribed communicates on the same server, it is sufficient for two objects wishing to communicate data between them to be subscribed to the same broker (server).
@damalgos, I just double-checked and I do have this scan button in the « Zigbee discovery » section.
Instance updated to version 4.7.2
Edit: my scan button has indeed disappeared.
Greetings!
I came across this article this morning and rather than opening a new thread, I’m posting it here to bump this post 
. If it’s a problem or a duplicate, we can move it
There appears to be a 40-device limit with Sonoff’s ZigBee dongle, and here’s how to remove it, if needed:
https://www.domo-blog.fr/comment-flasher-dongle-zigbee-sonoff/
By the way, we’d like to remind the guy that there’s more to life than Jeedom and HA!
Have a great day!
I’m not far from 40 devices, I’ll save it to my bookmarks.
I’ll certainly need it.
Thanks.
Exactly! 
Don’t hesitate to mention Gladys when you see that kind of content