Csi.sock was not created in /var/lib/kubelet/plugins/pxd.portworx.com

I tried PX 2.6 in my on-premise k8s cluster, the install spec file was generated by PX-Central . But when I create a CSI PVC, it’s in pending status, and I checked the related pods, found containers in px-csi-ext did not work correctly, the error log is “W0910 07:54:15.411770 1 connection.go:172] Still connecting to unix:///csi/csi.sock”. Also there was no csi.sock file in “/var/lib/kubelet/plugins/pxd.portworx.com”, and no CSI register socket file in “/var/lib/kubelet/plugins_registry”. Anyone knows the reason?

the k8s version is 1.15.6