When updating certificates in SDDC manager, you may get a retrust error similar to the following after manually completing the retrust out of band:
Could not establish retrust due to: Retrust with <some_appliance_fqdn> failed, with error null
VMware Cloud Foundation 5.1.1
This is due to a SDDC workflow issue.
Manually set the task to completed status in the SDDC manager database. Contact Broadcom VCF GS Support to complete this task as it will require editing multiple tables in platform DB.