iOS client cannot connect

Hello,

I have a Grinder, a Jigsaw Z-Wave, and a Jigsaw KNX. The 3 servers run bOS V4.4.4 and they are on different location / houses. 

I'm using multiple iPads and Android tablets in each locations ; everything is working fine.

I'm using the same iPhone - my iPhone- in the 3 locations. 

On the Grinder and Jigsaw KNX, no issues at all. 

On the Jigsaw Z-Waver, my iPhone doesn't want to connect. I have to remove profiles on the bOS client, on the server, and reboot, to be able to connect back for a while... and then it's stuck again, and I have to remove profiles everywhere and reboot. And again again and again. Any ideas how to fix this once for good ? 

Thanks,

François