If you are expanding your VMware Cloud Foundation 9 management or workload domain and have more than one vMotion vmkernel not created by the VCF deployment, you will encounter this error. Broadcom Engineering should provide an option for administrators to create additional vmkernels for vMotion to support multiple stream helpers and increase data throughput on the vMotion network.
vMotion Information

Error Message
Host is not conforming with the requirement of single vmknic for vMotion/management traffic type.

Resolution
Host -> Configure -> Remove Second vMotion vmkernel.

Retry Workload Domain expansion

The operation was successful, and the workload domain is now ready for expansion.