Problems with "service principal names"

Hi,

I use Navision 2017 CU5 with a local server (ABCDNAV01) who is not a member of an active directory.
MSSQL2014SP2 and Navision are on the same machine. Both services uses a local service user (SQL - dbnav / NAV - navservice01). Both service user are allowed with local security policy to login as a service. Both service user are in the local administrator group.

If I start the navision instance I get the following issue in eventlog for each port

Server instance: DynamicsNAV100
Tenant: 
<ii>The service could not add service principal names because the service account could not be found in Active Directory.
Account: ABCDNAV01\navservice01
Service principal names:
DynamicsNAV/abcdnav01:7045
DynamicsNAV/abcdnav01:7045</ii>

On stop it is the same. only the message is different

The service could not remove service principal names because the service account could not be found in Active Directory.

With the default administrator account it's the same.
If the service is running, I can connect to Windows Client without problems.
I found some hints to fix setspn. But setspn won't work because the machine isn't an active directory member.