During the deployment of a VCF 9.0 environment where the VCF Installer is converted to the SDDC Manager as part of the process, the default interface for the appliances FQDN is changed to the SDDC Manager UI.
If a task fails after this process is complete, revisiting the appliances FQDN will show the SDDC Manager UI where there will not be a way to restart the failed task.
VCF 9.0
SDDC Manager 9.0
To get back into the VCF Installer UI, change the URL in the address bar to point directly at it.
https://<fqdn-of-vcf-installer>/vcf-installer-ui/