[kolla-ansible][neutron]BGP Problems

Hello, I'm trying to get BGP / BGP speaker / DRAgent to work with Neutron on one side and a Cisco router on the other. I work under Centos / Kolla-ansible / Wallaby. I adapt this technical documentation (https://docs.openstack.org/neutron/latest/admin/config-bgp-dynamic-routing.h...) to my configuration but I am having difficulties (the cisco router sends a TCP SYN frame to the router in Openstack, TCP port 179, but the router sends back an RST. I don't understand why, no security on the router port). Do you have any links to help, tutorials, that would be of great help to me. Thanks in advance.

Franck