When I try to use the addon I got this error -> SEVERE: Failed to connect

Directory Grid Renderers collection For Vaadin7
1

When I try to use the addon I got this error →

SEVERE: Failed to connect service https://wsc.vaadin.com/api/compiler/compile
[INFO]

[INFO]
Total time: 5.305 s
javax.ws.rs.InternalServerErrorException: HTTP 500 Internal Server Error
[INFO]
Finished at: 2018-05-31T13:17:04+03:00
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.handleErrorStatus(ClientInvocation.java:189)
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.extractResult(ClientInvocation.java:154)
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:444)
at org.jboss.resteasy.client.jaxrs.internal.ClientInvocationBuilder.post(ClientInvocationBuilder.java:201)
at com.vaadin.wscdn.client.Connection.queryRemoteWidgetSet(Connection.java:69)
at com.vaadin.integration.maven.UpdateWidgetsetMojo.triggerCdnBuild(UpdateWidgetsetMojo.java:168)
at com.vaadin.integration.maven.UpdateWidgetsetMojo.doExecute(UpdateWidgetsetMojo.java:86)
at org.codehaus.mojo.gwt.shell.AbstractGwtShellMojo.execute(AbstractGwtShellMojo.java:182)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
at org.codehaus.classworlds.Launcher.main(Launcher.java:47)

[INFO]
Final Memory: 24M/57M
[INFO]

[ERROR]
Failed to execute goal com.vaadin:vaadin-maven-plugin:8.3.3:update-widgetset (default) on project reeskont-vaadin: Remote widgetset compilation failed: (no response) → [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/MojoExecutionException

Process finished with exit code 1

2

Based on the log you are using Widgetset in CDN, i.e. cloud mode, and you have been unlucky since the server has rebooted itself during downloading the Widgetset, hence you got HTTP 500. I recommend just to try again.