I found the following in Q/A:

QUOTE ON:
When I click on the CPID link on the host page I get the following message: "The host doesn't exist in BOINC Combined or doesn't have credit". But my host does have credit.

Every time the client attaches to a new project it generates a new Host CPID. This host CPID is then sent to all the projects. The projects will then include the new host CPID in their next XML export and BOINCstats will pick it up on the next update. So at least a day is needed in order for the stats to get lined up.
QUOTE OFF.

Somewhat similar to my problem.
But it doesn't/hasn't worked for me.
Three host show correct owner, the rest ist n/a.
How can I add the missing owner info?

Wish you, and everybody else, a healthy Year 2020 !!

Since no-one is responding (I guess it is holiday time), I will explain more detailed:

1. LOGON to BOINC STATS
2. In the left menu click on "BAM"
3. click on "Hosts"
4. go to the untitled colum ("detailed stats" pop-up shows), click the "little blue pictogram"
5. go to the line named "Owner" and I see the value "n/a"
6. clicking on this ("n/a&quot gives me the above cited status/error message
7. three of my rigs show me corecctly as owner, the rest does not
8. how can I solve this?

Hope you all had a good start into 2020 ...

Here is an URL to show the situation:
https://www.boincstats.com/stats/-1/host/detail/a005d22401beb24f0a2daeb53f1137d8
Maybe this will motivate someone to answer ...