Should the time on VoIP Detective appear to be off (the current time is shown on the "Your Account" page), you can correct this by syncing it with your VMware ESXi host.
The below examples are from ESXi 6.5, so your experience may be slightly different.
Edit the settings on the VoIP Detective virtual machine, and choose the "VM Options" tab
Expand the VMware Tools option, and scroll down to Time. Be sure this box "Synchronize guest time with host"
At this point, VoIP Detective will be in sync with your ESXi host. You are likely finished now. If the time still appears off, you may need to verify that the NTP service on your host is setup and active. To do this, click on "Host" on the upper left, and verify that the time is correct under the "System Information" section.
This guide should walk you through enabling NTP on your host: