Two major issues seem to be resolved and I hope this helps others.
When deploying New-OfficeWebAppsFarm on Office Online Server or Office Web Apps Server fails with:
Faulting application name: microsoft.office.web.agentmanager.exe, version: 16.0.10360.20000, time stamp: 0x5eba11c5 Faulting module name: KERNELBASE.dll, version: 10.0.14393.3986, time stamp: 0x5f77fd5b
Try adding registry key “HKLM\SYSTEM\CurrentControlSet\services\eventlog\Microsoft Office Web Apps” because in our case, the key could not be located.
When getting the following SSL/TLS validation errors:
ExcelServicesWfeWatchdog reported status for ExcelServicesWfe in category ‘WfeHealth’. Reported status: Got CommunicationException when running WFE watchdog health test: System.ServiceModel.Security.SecurityNegotiationException: Could not establish trust relationship for the SSL/TLS secure channel with authority …… System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.
Recreate your SSL certificate to include the machine FQDN name in the secondary alternative name (SAN) field of the certificate.