Please attach the file in the exception.

Also, are you sure you are on 2.40.4? I fixed an issue in 2.40.4 that was causing this. If you upgraded the plugin, did you restart Jenkins?

file attached, suffix,smtphost,recipientList,defaultReplyTo replaced

yes plugin list show 2.40.4 and more than one time restarted

Actually, it looks like my full fix didn't get merged in from my work. Attached is a version of the plugin with the full fix. If you are willing, please give it a shot.

I used the Advanced tab to install the provided version and restarted
Now I get the following error:

WARNING: Failed to instantiate Key[type=hudson.plugins.emailext.ExtendedEmailPublisherDescriptor, annotation=[none]]; skipping this component
com.google.inject.ProvisionException: Guice provision errors:

1) Tried proxying hudson.plugins.emailext.ExtendedEmailPublisherDescriptor to support a circular dependency, but it is not an interface.

1 error
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:52)
at com.google.inject.Scopes$1$1.get(Scopes.java:65)
at hudson.ExtensionFinder$GuiceFinder$FaultTolerantScope$1.get(ExtensionFinder.java:428)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
at com.google.inject.internal.InjectorImpl$3$1.call(InjectorImpl.java:1005)
at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1058)
at com.google.inject.internal.InjectorImpl$3.get(InjectorImpl.java:1001)
at hudson.ExtensionFinder$GuiceFinder._find(ExtensionFinder.java:390)
at hudson.ExtensionFinder$GuiceFinder.find(ExtensionFinder.java:381)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:386)
at hudson.ExtensionList.load(ExtensionList.java:349)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:287)
at hudson.ExtensionList.iterator(ExtensionList.java:156)
at jenkins.model.Jenkins.getDescriptorByType(Jenkins.java:1197)
at hudson.plugins.emailext.ExtendedEmailPublisherDescriptor.readResolve(ExtendedEmailPublisherDescriptor.java:458)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:95)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:56)
at java.lang.reflect.Method.invoke(Method.java:620)
at com.thoughtworks.xstream.converters.reflection.SerializationMethodInvoker.callReadResolve(SerializationMethodInvoker.java:66)
at hudson.util.RobustReflectionConverter.unmarshal(RobustReflectionConverter.java:229)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)
at com.thoughtworks.xstream.core.AbstractReferenceUnmarshaller.convert(AbstractReferenceUnmarshaller.java:65)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:66)
at com.thoughtworks.xstream.core.TreeUnmarshaller.convertAnother(TreeUnmarshaller.java:50)
at com.thoughtworks.xstream.core.TreeUnmarshaller.start(TreeUnmarshaller.java:134)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.unmarshal(AbstractTreeMarshallingStrategy.java:32)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:1189)
at hudson.util.XStream2.unmarshal(XStream2.java:113)
at com.thoughtworks.xstream.XStream.unmarshal(XStream.java:1173)
at hudson.XmlFile.unmarshal(XmlFile.java:163)
at hudson.model.Descriptor.load(Descriptor.java:783)
at hudson.plugins.emailext.ExtendedEmailPublisherDescriptor.<init>(ExtendedEmailPublisherDescriptor.java:344)
at hudson.plugins.emailext.ExtendedEmailPublisherDescriptor$$FastClassByGuice$$5dfa54d0.newInstance(<generated>)
at com.google.inject.internal.cglib.reflect.$FastConstructor.newInstance(FastConstructor.java:40)
at com.google.inject.internal.DefaultConstructionProxyFactory$1.newInstance(DefaultConstructionProxyFactory.java:61)
at com.google.inject.internal.ConstructorInjector.provision(ConstructorInjector.java:108)
at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:88)
at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:269)
at com.google.inject.internal.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:46)
at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1058)
at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
at com.google.inject.Scopes$1$1.get(Scopes.java:65)
at hudson.ExtensionFinder$GuiceFinder$FaultTolerantScope$1.get(ExtensionFinder.java:428)
at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
at com.google.inject.internal.InjectorImpl$3$1.call(InjectorImpl.java:1005)
at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1051)
at com.google.inject.internal.InjectorImpl$3.get(InjectorImpl.java:1001)
at hudson.ExtensionFinder$GuiceFinder._find(ExtensionFinder.java:390)
at hudson.ExtensionFinder$GuiceFinder.find(ExtensionFinder.java:381)
at hudson.ClassicPluginStrategy.findComponents(ClassicPluginStrategy.java:386)
at hudson.ExtensionList.load(ExtensionList.java:349)
at hudson.ExtensionList.ensureLoaded(ExtensionList.java:287)
at hudson.ExtensionList.iterator(ExtensionList.java:156)
at jenkins.model.Jenkins.getDescriptorByType(Jenkins.java:1197)
at hudson.plugins.copyartifact.BuildSelectorParameter.initAliases(BuildSelectorParameter.java:135)
at hudson.plugins.copyartifact.CopyArtifactPlugin.postInitialize(CopyArtifactPlugin.java:35)
at hudson.PluginManager$2$1$2.run(PluginManager.java:390)
at org.jvnet.hudson.reactor.TaskGraphBuilder$TaskImpl.run(TaskGraphBuilder.java:169)
at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:282)
at jenkins.model.Jenkins$7.runTask(Jenkins.java:905)
at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:210)
at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:117)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1157)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:627)
at java.lang.Thread.run(Thread.java:801)

any updates?

Please try this new hpi

it is working.

Will be releasing 2.40.5 soon