Quando meu projeto do Android 23 tenta se conectar ao meu servidor via HTTPS, tudo fica bem.

Se eu alternar o SDK de destino para 24, recebo o seguinte erro:

 javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
     at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:361)
     at android.net.SSLCertificateSocketFactory.verifyHostname(SSLCertificateSocketFactory.java:198)
     at android.net.SSLCertificateSocketFactory.createSocket(SSLCertificateSocketFactory.java:443)
     at org.apache.http.conn.ssl.SSLSocketFactory.createSocket(SSLSocketFactory.java:394)
     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:170)
     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:169)
     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:124)
     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:366)
     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:560)
     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:492)
     at com.worklight.wlclient.WLRequestSender.run(WLRequestSender.java:47)
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
     at java.lang.Thread.run(Thread.java:761)
 Caused by: java.security.cert.CertificateException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.
     at com.android.org.conscrypt.TrustManagerImpl.verifyChain(TrustManagerImpl.java:563)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:444)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:508)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrustedRecursive(TrustManagerImpl.java:508)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:401)
     at com.android.org.conscrypt.TrustManagerImpl.checkTrusted(TrustManagerImpl.java:375)
     at com.android.org.conscrypt.TrustManagerImpl.getTrustedChainForServer(TrustManagerImpl.java:304)
     at android.security.net.config.NetworkSecurityTrustManager.checkServerTrusted(NetworkSecurityTrustManager.java:94)
     at android.security.net.config.RootTrustManager.checkServerTrusted(RootTrustManager.java:88)
     at com.android.org.conscrypt.Platform.checkServerTrusted(Platform.java:178)
     at com.android.org.conscrypt.OpenSSLSocketImpl.verifyCertificateChain(OpenSSLSocketImpl.java:596)
     at com.android.org.conscrypt.NativeCrypto.SSL_do_handshake(Native Method)
     at com.android.org.conscrypt.OpenSSLSocketImpl.startHandshake(OpenSSLSocketImpl.java:357)
    ... 13 more
 Caused by: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

Voltar para 23 e funciona novamente.
Alguma coisa mudou em 24 em relação aos requisitos mínimos para certificados?