play-scala-grpc-example run exception

Cloned the play-samples on my machine, and followed the documentation for locally running the play-scala-grpc-example sample app, but received an exception when invoking curl --insecure https://localhost:9443/

Here's the exception on the server:

! @7mf0gi45h - Internal server error, for (GET) [https://localhost:9443/] ->

play.api.UnexpectedException: Unexpected exception[StatusRuntimeException: UNAVAILABLE: io exception
Channel Pipeline: [SslHandler#0, ProtocolNegotiators$ClientTlsHandler#0, WriteBufferingAndExceptionHandler#0, DefaultChannelPipeline$TailContext#0]]
	at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:358)
	at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:264)
	at play.core.server.AkkaHttpServer$$anonfun$2.applyOrElse(AkkaHttpServer.scala:430)
	at play.core.server.AkkaHttpServer$$anonfun$2.applyOrElse(AkkaHttpServer.scala:422)
	at scala.concurrent.Future.$anonfun$recoverWith$1(Future.scala:417)
	at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:41)
	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
	at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:63)
	at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:100)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
Caused by: io.grpc.StatusRuntimeException: UNAVAILABLE: io exception
Channel Pipeline: [SslHandler#0, ProtocolNegotiators$ClientTlsHandler#0, WriteBufferingAndExceptionHandler#0, DefaultChannelPipeline$TailContext#0]
	at io.grpc.Status.asRuntimeException(Status.java:533)
	at akka.grpc.internal.UnaryCallAdapter.onClose(UnaryCallAdapter.scala:40)
	at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:413)
	at io.grpc.internal.ClientCallImpl.access$500(ClientCallImpl.java:66)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:742)
	at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:721)
	at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
	at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:123)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
Caused by: javax.net.ssl.SSLHandshakeException: General OpenSslEngine problem
	at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslEngine.handshakeException(ReferenceCountedOpenSslEngine.java:1771)
	at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslEngine.wrap(ReferenceCountedOpenSslEngine.java:776)
	at javax.net.ssl.SSLEngine.wrap(SSLEngine.java:511)
	at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.wrap(SslHandler.java:1079)
	at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.wrapNonAppData(SslHandler.java:970)
	at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1443)
	at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1275)
	at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1322)
	at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501)
	at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:440)
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:456)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:323)
	at sun.security.validator.Validator.validate(Validator.java:271)
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:315)
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:278)
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141)
	at io.grpc.netty.shaded.io.netty.handler.ssl.OpenSslTlsv13X509ExtendedTrustManager.checkServerTrusted(OpenSslTlsv13X509ExtendedTrustManager.java:223)
	at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslClientContext$ExtendedTrustManagerVerifyCallback.verify(ReferenceCountedOpenSslClientContext.java:261)
	at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslContext$AbstractCertificateVerifier.verify(ReferenceCountedOpenSslContext.java:700)
	at io.grpc.netty.shaded.io.netty.internal.tcnative.SSL.readFromSSL(Native Method)
	Suppressed: javax.net.ssl.SSLHandshakeException: error:1000007d:SSL routines:OPENSSL_internal:CERTIFICATE_VERIFY_FAILED
		at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslEngine.sslReadErrorResult(ReferenceCountedOpenSslEngine.java:1287)
		at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslEngine.unwrap(ReferenceCountedOpenSslEngine.java:1248)
		at io.grpc.netty.shaded.io.netty.handler.ssl.ReferenceCountedOpenSslEngine.unwrap(ReferenceCountedOpenSslEngine.java:1324)
		at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler$SslEngineType$1.unwrap(SslHandler.java:201)
		at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1380)
		at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1275)
		at io.grpc.netty.shaded.io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1322)
		at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501)
		at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:440)
		at io.grpc.netty.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
	at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
	at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:451)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:323)
	at sun.security.validator.Validator.validate(Validator.java:271)
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:315)
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:278)
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141)
	at io.grpc.netty.shaded.io.netty.handler.ssl.OpenSslTlsv13X509ExtendedTrustManager.checkServerTrusted(OpenSslTlsv13X509ExtendedTrustManager.java:223)

Using following java version on OSX 11.6.2:

openjdk version "1.8.0_312"
OpenJDK Runtime Environment (build 1.8.0_312-bre_2021_10_20_23_15-b00)
OpenJDK 64-Bit Server VM (build 25.312-b00, mixed mode)

Start with the locally running documentation for the play-scala-grpc-example and reproduce the failure using curl --insecure https://localhost:9443/. Trace the SSLHandshakeException and certificate-validation error; done means the sample starts locally and the curl request no longer produces the internal server error.