Istio 1.6.7 : VM based Proxy Not Working

We are trying to enroll a CentOS7 VM into existing service mesh using the doc -

Getting into - external/envoy/source/common/config/] gRPC config for rejected: Error adding/updating listener(s) Didn’t find a registered implementation for name: ‘istio.alpn’

THE proxy-status return LDS as stale , and RDS as not sent , while CDS is synced.

Any pointers on the issues?