API Gateway generated SDK: "No such host is known."

I've generated an SDK via the API Gateway UI, and when building a project with it as a dependency per the SDK instructions I get the following error when trying to hit any of the APIs:

Exception in thread "main" com.amazonaws.SdkClientException: Unable to execute HTTP request: No such host is known (******.execute-api.eu-west-1.amazonaws.com)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.handleRetryableException(AmazonHttpClient.java:1189)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1135)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.doExecute(AmazonHttpClient.java:784)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeWithTimer(AmazonHttpClient.java:752)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.execute(AmazonHttpClient.java:726)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.access$500(AmazonHttpClient.java:686)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutionBuilderImpl.execute(AmazonHttpClient.java:668)
	at com.amazonaws.client.ClientHandlerImpl.doInvoke(ClientHandlerImpl.java:204)
	at com.amazonaws.client.ClientHandlerImpl.invoke(ClientHandlerImpl.java:185)
	at com.amazonaws.client.ClientHandlerImpl.execute(ClientHandlerImpl.java:93)
	at com.amazonaws.opensdk.protect.client.SdkClientHandler.execute(SdkClientHandler.java:42)
	at com.configuration.api.ConfigurationClient.getAllResults(ConfigurationClient.java:103)
	at connection.main(MainClass.java:15)
Caused by: java.net.UnknownHostException: No such host is known (******.execute-api.eu-west-1.amazonaws.com)
	at java.base/java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
	at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:929)
	at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1515)
	at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:848)
	at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1505)
	at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1364)
	at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298)
	at com.amazonaws.SystemDefaultDnsResolver.resolve(SystemDefaultDnsResolver.java:27)
	at com.amazonaws.http.DelegatingDnsResolver.resolve(DelegatingDnsResolver.java:38)
	at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:112)
	at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:374)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at com.amazonaws.http.conn.ClientConnectionManagerFactory$Handler.invoke(ClientConnectionManagerFactory.java:76)
	at com.amazonaws.http.conn.$Proxy3.connect(Unknown Source)
	at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:393)
	at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
	at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
	at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
	at com.amazonaws.http.apache.client.impl.SdkHttpClient.execute(SdkHttpClient.java:72)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeOneRequest(AmazonHttpClient.java:1311)
	at com.amazonaws.http.AmazonHttpClient$RequestExecutor.executeHelper(AmazonHttpClient.java:1127)
	... 11 more