Is the client integration plugin detected in the browser. you can verify by going to the https://<vcenter fqdn> and click on webclient. If on the bottom bar, if you can see to download the client integration plugin then it confirms that the CIP is not detecting on the machine.
new browsers have NPAPI disabled and new security features recently changed settings leading to this problem.
You can try the steps in the below KB
Client Integration plugin is not recognized as installed after upgrading the browser in vCloud Direc...
Thanks,
MS
