Yes ,I often met this issue,but recently I find the way to solve this .
1.go to the ESXI host and edit the file /etc/hosts
2.add the FQDN of workbench into ESXI hosts file.such as
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vi /etc/hosts
192.168.10.1 esxi01.xxx.com esxi01
192.168.10.10 workbench.xxx.com workbench
--------------------------------------------------------------
3.intall STAF into ESXI host via workbench installation helper.
4.done well
My personal website
http://www.daimongu.com