Presuming this system was configured by our systems integrator; this system should perform DHCP Request on both the BMC and the on system NIC.
I have access to the DHCP server display of the IP issued and SSH into that system. The log in information is here: Default Login
If you do not have access to the DHCP server or some other method of determining the IP; then the alternative is to use either the RS232 ("Console" RJ45 on back of system), or use the BMC WebUI to access the KVM console. BMC authentication is UID/PWD: admin/password.
If you choose the BMC WebUI console on a ThunderX2 system; you will need to disable popup blocking as ThunderX2 systems use HTML5 and a pop up by default.
Once at the console; use the authentication information from that website. Then; you can see if it is on the network and get its IP using the 'ifconfig' command.
If it does not have an IP; then you can use the dhclient of other standard Linux commands to assign or request an IP from there.
Feel free to reply with any further questions. Or, go to support.phoenicselectronics.com and ask a question.