FailedConsole Output

<===[JENKINS REMOTING CAPACITY]===>channel started
Executing Maven:  -B -f /local/jenkins/jobs/taverna-activity-test-utils-maintenance/workspace/pom.xml -Dmaven.repo.local=/local/jenkins/jobs/taverna-activity-test-utils-maintenance/workspace/.repository clean install
[INFO] Scanning for projects...
[INFO] Initializing Artifactory Build-Info Recording
[HUDSON] Collecting dependencies info[INFO] 
[INFO] Using the builder org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder with a thread count of 1

[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building Taverna activity test utils 1.6-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] Downloading: http://repository.mygrid.org.uk/artifactory/repo/net/sf/taverna/t2/infrastructure/2.6-SNAPSHOT/infrastructure-2.6-20140514.092153-1.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:04 min
[INFO] Finished at: 2014-05-14T16:25:25+00:00
[INFO] Final Memory: 11M/88M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project activity-test-utils: Could not resolve dependencies for project net.sf.taverna.t2.activities:activity-test-utils:jar:1.6-SNAPSHOT: Failed to collect dependencies at net.sf.taverna.t2.core:workflowmodel-impl:jar:1.6-SNAPSHOT -> net.sf.taverna.t2.core:workflowmodel-api:jar:1.6-SNAPSHOT -> net.sf.taverna.t2.infrastructure:spi-discovery-api:jar:2.6-SNAPSHOT: Failed to read artifact descriptor for net.sf.taverna.t2.infrastructure:spi-discovery-api:jar:2.6-SNAPSHOT: Could not transfer artifact net.sf.taverna.t2:infrastructure:pom:2.6-20140514.092153-1 from/to mygrid-snapshot-repository (http://repository.mygrid.org.uk/artifactory/repo): Failed to transfer file: http://repository.mygrid.org.uk/artifactory/repo/net/sf/taverna/t2/infrastructure/2.6-SNAPSHOT/infrastructure-2.6-20140514.092153-1.pom. Return code is: 503, ReasonPhrase: Service Temporarily Unavailable. -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException