diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/data/DataSetUploadForm.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/data/DataSetUploadForm.java
index 7f1e2d5cdb3a205ad590dae08d84a0295b5da41b..72bac5702c2b54d6dffca70fbb515dd651cbc3b2 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/data/DataSetUploadForm.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/data/DataSetUploadForm.java
@@ -16,6 +16,8 @@
 
 package ch.systemsx.cisd.openbis.generic.client.web.client.application.ui.data;
 
+import com.google.gwt.http.client.URL;
+
 import ch.systemsx.cisd.openbis.generic.client.web.client.application.CommonViewContext;
 import ch.systemsx.cisd.openbis.generic.client.web.client.application.Dict;
 import ch.systemsx.cisd.openbis.generic.client.web.client.application.GenericConstants;
@@ -116,7 +118,7 @@ public class DataSetUploadForm extends AbstractRegistrationForm
         URLMethodWithParameters url = new URLMethodWithParameters(cifexUrl);
         url.addParameter(BasicConstant.CIFEX_URL_PARAMETER_COMMENT, comment);
         url.addParameter(BasicConstant.CIFEX_URL_PARAMETER_RECIPIENT, recipient);
-        return url.toString();
+        return URL.encode(url.toString());
     }
 
 }
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/BasicConstant.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/BasicConstant.java
index 20035c3fd014a0e806ec0a77d99b282fcf33a803..8c027f0e4018b563c15b0e7062ccba24943a2490 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/BasicConstant.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/basic/BasicConstant.java
@@ -29,13 +29,14 @@ public class BasicConstant
     /** Maximum length of a comment for uploading data sets to CIFEX. */
     public static final int MAX_LENGTH_OF_CIFEX_COMMENT = 1000;
 
-    private BasicConstant()
-    {
-    }
-
     /** Cifex URL parameter 'comment' */
     public static final String CIFEX_URL_PARAMETER_COMMENT = "comment";
 
     /** Cifex URL parameter 'recipient' */
-    public static final String CIFEX_URL_PARAMETER_RECIPIENT = "recipient";
+    public static final String CIFEX_URL_PARAMETER_RECIPIENT = "recipients";
+
+    private BasicConstant()
+    {
+    }
+
 }