Error message in SDDC Manager :
Looking at /var/log/vmware/vcf/domainmanager/domainmanager.log we see the following :
com.vmware.evo.sddc.common.core.error.InvalidStateException","message":"Failed to execute vROps insertion operation on SDDC
SDDC Manger Version 4.5
vCenter Version 8.x
Root password of the cloud proxy was expired on the Aria operations which resulted in the SSH connection failure between the VMware Aria Suite Lifecycle Manager and cloud proxy leading to certificate install failure.
Reset the root password of the cloud proxy and rerun the certificate operation on the SDDC manager
Refer to How to reset the root password in Cloud proxy.