So checking the install guide for 9.1 (https://support.brightcomputing.com/manuals/9.1/installation-manual.pdf27) the minimum head node requirements are
• x86-64, or ARMv8 CPU
• 4GB RAM • 80GB diskspace
• 2 Gigabit Ethernet NICs (for the most common Type 1 topology (section 3.3.9))
• DVD drive or USB drive
So it seems you are well within the right bounds there when it comes to memory/disk. Do you have dual NIC's in the workstation VM?
Also have you applied the license key (request-license) What about DNS config, ntp are they all working correctly? If you SSH in is there anything in /var/log/messages or /var/log/syslog?