I just faced the exact same issue and was hoping if someone can help:
I've setup a small lab for Horizon 7. The strange thing is when i create an instant pool i cannot select the Vcenter Server. However when I select Full Clones the Vcenter Server information pops up and im able to proceed. Now because of this I'm unable to create Instant Clone Pool. My Vcenter is 6.7, Esxi is 6.5. There is one strange thing which i noticed on Vcenter, it gives a warning that your evaluation license will expire. However I have added a production license using the console. So in short Horizon has Production Enterprise License, Esxi has Production License.
Can anyone please let me know what could be the issue.
Were you able to find an answer to this please. I'm caught up in the exact same situation after so many years. I have ESXI 6.5, Vsphere 6.5, Vcenter 6.7, Horizon 7.5.
I only get the Vcenter Option when I select to create Full Clones. I've added Enterprise Licenses to Horizon and can see that Instant Clone feature is active. Can you please help