Offliner fails to download few artifacts

List of .jar files:

• /io/confluent/kafka-schema-registry-client/5.3.0/kafka-schema-registry-client-5.3.0.jar
• /org/knopflerfish/kf6/log-API/5.0.0/log-API-5.0.0.jar
• /org/apache/servicemix/bundles/org.apache.servicemix.bundles.xercesImpl/2.12.0_1/org.apache.servicemix.bundles.xercesImpl-2.12.0_1.jar
• /log4j/log4j/1.2.14-patch-01/log4j-1.2.14-patch-01.jar
• /org/eclipse/jetty/cdi/cdi-servlet/9.4.20.v20190813/cdi-servlet-9.4.20.v20190813.jar
• /org/springframework/boot/spring-boot-test/1.5.19.RELEASE/spring-boot-test-1.5.19.RELEASE-tests.jar
• /io/confluent/common-utils/5.3.0/common-utils-5.3.0.jar
• /org/apache/felix/org.apache.felix.main/5.6.12/org.apache.felix.main-5.6.12.jar
• /org/apache/logging/log4j/log4j-api-scala_2.11/2.12.1/log4j-api-scala_2.11-2.12.1.jar
• /com/google/inject/guice/3.0/guice-3.0-no_deps.jar
• /xom/xom/1.2.10/xom-1.2.10.jar
• /org/easymock/easymockclassextension/3.4/easymockclassextension-3.4.jar
• /org/optaplanner/optaplanner-test/7.14.0.Final-redhat-00004/optaplanner-test-7.14.0.Final-redhat-00004-tests.jar
• /io/confluent/common-config/5.3.0/common-config-5.3.0.jar
• /org/eclipse/jetty/cdi/cdi-core/9.4.20.v20190813/cdi-core-9.4.20.v20190813.jar
• /com/fasterxml/jackson/dataformat/jackson-dataformat-ion/2.8.11/jackson-dataformat-ion-2.8.11.jar
• /org/wildfly/core/wildfly-self-contained/6.0.15.Final-redhat-00001/wildfly-self-contained-6.0.15.Final-redhat-00001.jar
• /org/apache/logging/log4j/log4j-nosql/2.12.1/log4j-nosql-2.12.1.jar
• /org/springframework/cloud/spring-cloud-stream-binder-kafka-test-support/1.1.2/spring-cloud-stream-binder-kafka-test-support-1.1.2.jar
• /org/eclipse/emf/org.eclipse.emf.edit/2.8.0-v20120917-0436/org.eclipse.emf.edit-2.8.0-v20120917-0436.jar
• /org/apache/activemq/artemis-native/2.9.0.redhat-00005/artemis-native-2.9.0.redhat-00005.jar
• /io/confluent/kafka-avro-serializer/5.3.0/kafka-avro-serializer-5.3.0.jar
• /org/springframework/boot/spring-boot/1.5.19.RELEASE/spring-boot-1.5.19.RELEASE-tests.jar
• /isorelax/isorelax/20050331/isorelax-20050331.jar
• /org/eclipse/jetty/jetty-infinispan/9.4.20.v20190813/jetty-infinispan-9.4.20.v20190813.jar
• /org/apache/logging/log4j/log4j-api-scala_2.10/2.12.1/log4j-api-scala_2.10-2.12.1.jar

other than .jar files are uploaded as attachment.