Hi @matteobruschi and welcome to the Cayenne community!
This definitely looks like the behavior of our agent software when running on a Pi with the 4.9 Linux kernel. You can check your kernel version with the command
Please see this post for some options on how you can resolve this -- either by downgrading the kernel to 4.4 (if you don't need 4.9 -- most people don't), or with a beta Pi agent that doesn't have this particular limitation.
We'll be updating the main agent to have support for the 4.9 kernel in the near future.