We notice the ssconfig of the Cell Manager doesn't contain the thumbprint of the Vcenter
Ideally after registering the plugin, the thumbprint of the Vcenter should show on the ssconfig of CM like this:
However in this case, after registering plugin, the thumbprint has been added and then removed immediately without reason. even on DP GUI, it display "successfully register plugin"
To workaround this issue, we export the Vcenter and then reimport it, while importing vcenter, we select option "HTML 5 GRE plugin"
Now the plugin is registered successfully.