Jboss Https configuration with p7b certificate fails - https

Question

We are implementing Http to Https conversion for our application, which uses Jboss as the application server. We made the following changes in the standalone.xml file.
<subsystem xmlns="urn:jboss:domain:web:1.1" native="false" default-virtual-server="default-host">
<connector name="http" protocol="HTTP/1.1" scheme="http" socket-binding="http" redirect-port="8443"/>
<connector name="https" protocol="HTTP/1.1" scheme="https" socket-binding="https" enable-lookups="false" secure="true">
<ssl name="ssl" key-alias="mykey" password="changeit" certificate-key-file="C:\Programs\Siemens\JBoss7.1.0\domain\configuration\winstore.jks" protocol="TLSv1" verify-client="false"/>
</connector>
<virtual-server name="default-host" enable-welcome-root="false">
<alias name="localhost"/>
<alias name="example.com"/>
</virtual-server>
</subsystem>
The keystore command lists the presence of the key as below:
[code=java]C:\Programs\Siemens\JBoss7.1.0\domain\configuration>keytool -list -keystore C:\Programs\Siemens\JBoss7.1.0\domain\configuration\winstore.jks
Enter keystore password:
Keystore type: JKS
Keystore provider: SUN
Your keystore contains 1 entry
mykey, Jun 23, 2017, trustedCertEntry,
Certificate fingerprint (SHA1): 8D:64:10:8B:F6:0D:1E:17:01:52:1C:97:8A:89:75:80:2D:2F:45:6B
We received the certificate from our certification team in p7b format, which we had to convert to CER format and then add it to keystore - winstore.jks which we are using in the path above. But with the above configurations in place, we are getting the below error while trying to restart jBoss.
11:46:19,692 ERROR [org.apache.coyote.http11.Http11Protocol] (MSC service thread 1-4) Error initializing endpoint: java.io.IOException: Alias name mykey does not identify a key entry
at org.apache.tomcat.util.net.jsse.JSSESocketFactory.getKeyManagers(JSSESocketFactory.java:517) [jbossweb-7.0.10.Final.jar:]
at org.apache.tomcat.util.net.jsse.JSSESocketFactory.init(JSSESocketFactory.java:452) [jbossweb-7.0.10.Final.jar:]
at org.apache.tomcat.util.net.jsse.JSSESocketFactory.createSocket(JSSESocketFactory.java:168) [jbossweb-7.0.10.Final.jar:]
at org.apache.tomcat.util.net.JIoEndpoint.init(JIoEndpoint.java:977) [jbossweb-7.0.10.Final.jar:]
at org.apache.coyote.http11.Http11Protocol.init(Http11Protocol.java:190) [jbossweb-7.0.10.Final.jar:]
at org.apache.catalina.connector.Connector.init(Connector.java:983) [jbossweb-7.0.10.Final.jar:]
at org.jboss.as.web.WebConnectorService.start(WebConnectorService.java:267) [jboss-as-web-7.1.0.Final.jar:7.1.0.Final]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_75]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_75]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_75]
Please let us know what could be the potential problem as these are our initial steps towards understanding Https.
Please note that if the certificate is a self signed one, the problem is not coming into picture.
Thanks,
Pavan.2