Your team's GitLab CE pipeline builds a Nautobot-driven network automation solution. The 'simulate' stage successfully starts a CML topology and prints the management IPs of two IOS-XE nodes. The next 'deploy' stage runs a Python script that pushes VLAN config over RESTCONF, but every device fails with a connection timeout. The 'simulate' and 'deploy' jobs run on the same GitLab runner but are separate jobs. The CML lab confirms the nodes are reachable from the CML host. What is the MOST likely cause of the deploy-stage failure?