If you are getting an error similiar to the one mentioned below the problem is with the signer as the signer may need to be added to local trust store.

Stack trace: javax.net.ssl.SSLHandshakeException: com.ibm.jsse2.util.h: No trusted certificate found
at com.ibm.jsse2.n.a(n.java:18)
at com.ibm.jsse2.jc.a(jc.java:463)
at com.ibm.jsse2.db.a(db.java:179)
at com.ibm.jsse2.db.a(db.java:107)
at com.ibm.jsse2.eb.a(eb.java:83)
at com.ibm.jsse2.eb.a(eb.java:237)
at com.ibm.jsse2.db.m(db.java:56)
at com.ibm.jsse2.db.a(db.java:174)
at com.ibm.jsse2.jc.a(jc.java:579)
at com.ibm.jsse2.jc.g(jc.java:168)

On WAS 6.1 : SSL certificate and key management > Key stores and certificates > NodeDefaultTrustStore > Signer certificates > Retrieve from port
On WAS 6.0 and below: You will need to run ikeyman to export/ import the signer certificates to the trust store.

Also, set JVM property javax.net.debug=true in order to get more detailed info on the error.