diff -ur voms-clients-3.0.7.orig/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java voms-clients-3.0.7/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java
--- voms-clients-3.0.7.orig/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java	2016-09-09 12:06:42.000000000 +0200
+++ voms-clients-3.0.7/src/main/java/org/italiangrid/voms/clients/impl/DefaultVOMSProxyInitBehaviour.java	2018-01-05 16:34:10.919346599 +0100
@@ -457,12 +457,12 @@
     if (params.isLimited())
       limitProxy(proxyOptions);
 
-    if (acs != null && !acs.isEmpty())
-      proxyOptions.setAttributeCertificates(
-        acs.toArray(new AttributeCertificate[acs.size()]));
-
     try {
 
+      if (acs != null && !acs.isEmpty())
+        proxyOptions.setAttributeCertificates(
+          acs.toArray(new AttributeCertificate[acs.size()]));
+
       ProxyCertificate proxy = ProxyGenerator.generate(proxyOptions,
         credential.getKey());