The latest versions of VMware ESXi 7.0/8.0 perform security checks on the build certificates of .ova and .ovf files before allowing you to use those files. See https://kb.vmware.com/s/article/84240.
For IP Office.ova files, you must upload the AvayaIPOffice-2023-OVA-CertChain.crt file to VMware. You only need to perform this process once.