TLS Certificate guides
The new “Staat der Nederlanden Private Root CA – G1” certificate chain, that is used by the new api.kvk.nl certificate, is by default not trusted by your application. Therefore you need to add the new chain to your trust-list.
Root and intermediate certificates
You can use https://ssltest.kvk.nl to test if you have correctly added the new root and intermediate certificates to your system or application. SSLtest uses the same root and intermediate chain as the new api.kvk.nl certificate.