If it appears when logging in to the ESXi host “Permission to perform this operation was denied”，And login to vCSA is no problem，Then it may be caused by the ``locked mode'' enabled in vCenter Server。
◎ Click "ESXi Host"-"Settings"-"Security Profile" in order，Click "Edit" in lock mode。
◎ Select [Disabled]，You can log in to the ESXi host。
[Reference]
- vpshere6 ESXI forbidden to log in，Permission to perform this operation is denied_milestone-CSDN blog _ permission to perform this operation is denied
