Trying to access vRA portal and getting "404 page not found" error.
Using DNS alias or CNAME is not supported with vRealize Automation 8.x.
vRealize Automation is only accessible through the FQDN used during deployment.
If you do not want to access vRealize Automation by the name of the host then you can do scale out and specify the desired name of the load balancer address to be used for access.
Placing a Load balancer in front of a single vRealize Automation 8.x node is not a supported configuration.
https://docs.vmware.com/en/VMware-vRealize-Suite-Lifecycle-Manager/8.10/com.vmware.vrsuite.lcm.8.10.doc/GUID-26003B0F-69E3-4D30-8625-64C000D5A12F.html
The vRealize Automation portal is not accessible