External network in OpenStack (combined with Tungsten Fabric) issue

Hello everyone, I've deployed OpenStack and Tungsten Fabric.
My model has 2 node: Deloy-node (1 NIC) and Target-node (1 NIC), the OS: CentOS 7.9. I used Ansible-deployer to deploy this model.
When deployed completely, I create VM (ubuntu 18.04) in OpenStack (create self-service network first), I configured the password in the Horizon (dashboard) so I can console to the VM without SSH. I try to choose SNAT option for the network (Tungsten Fabric webUI). Therefore, I can ping to Internet (Google, 8.8.8.8, ...) from the VM (ping google.com successfully), but when I try to install packages, it failed, it noticed: cannot connect to network, connect to nova.clouds.ubuntu.com failed, etc
So what should I do to install packages and use floating IP? Thanks before.