In interface vShield Manager in category Network virtualization (Preparation) Status of network connectivity for VXLAN traffic - Not ready.
Agent VXLAN was installed on host in automatic mode and for test has been reinstalled, agent work fine.
DHCP works fine and ip address has been assigned. Host m-esxi02 and m-esxi04 have addresses but the first host (m-esxi02) with status "Not ready".
How to change status to ready and how to assign address for new host?
There are multiple reasons for Host-not ready status . If Vibs are not available,if there is a communication issue between Host-VC-VCNS etc .. Most of the cases VCNS,VC&ESXI host logs are helpful . You should certainly check that once also you could try below step
Try creating a test cluster and move the host(In your case host 2 & 6) to that cluster and move the host back to original cluster.
VMware recommends to migrate to NSX as per this KB End of Availability (EOA) of VMware vCloud Networking and Security (vCNS) in VMware vCloud Suite 6.0...
I can see one of your host is prepared, there could be configuration differences between those ESXi hosts.
Check ESXi host logs > /var/log/esxupdate.log in ESXi host
and check eam logs > eam.log in vCenter Server. ProgramData/VMware/VMware VirtualCenter/Logs/ for Windows vCenter or /storage/log/vmware/vpx/eam.log for Linux vCenter
see if you found some error there
You can also double check your DNS resolution, NTP, and if you have vSphere Update Manager (VUM), check if the VUM is on
If its installed but VUM is off, you would need to bypass that see this KB: “Agent VIB module not installed” when installing VXLAN Agent using VUM (2053782) | VMware KB
Check out these 2 blog posts too and see if any of those helps