It seems that there's a problem with the Entrust signing cert (or the availability on it on some systems)
All of my VBR console installations have failed with a signing error and I have had to do this recently for every Veeam Console installation I have run (standalone):
PS:
Thank you for your inputs. This appears to be caused by outdated certificates.
Veeam documents the trusted root certificates required for Veeam Backup & Replication to operate correctly.
Once the required certificates are installed, everything should work as expected.