impossible to connect my monitor to the network

[insight870]

Hi, I have a serious issue with the network connection for the M100 monitor. Indeed when I start the installation with my iphone everything works until the last step. I show the QR code at the camera and the LED become green. I press next and the wifi connection is a success. But when the program try to connect to the monitor, the LED become orange and the installation fail.
I've tried the installation on an other place and it works directly. I doesn't understand why because this is the same infrastructure with the same adsl box.

What I have already tried:

• reset the monitor
• reset the modem/routeur
• reset the iphone
• reinstall the iphone app
• create an new account
• change to a WPA2 key
• change the wifi channel
• desactivate the router's firewall

But no change.

Somebody have an other idea?
thanks in advance.