Index: /trunk/src/org/openstreetmap/josm/io/OsmApiException.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/io/OsmApiException.java	(revision 15084)
+++ /trunk/src/org/openstreetmap/josm/io/OsmApiException.java	(revision 15085)
@@ -221,5 +221,5 @@
                 sb.append(tr(header));
             }
-            if (body != null && !body.isEmpty()) {
+            if (body != null && !body.isEmpty() && !body.equals(header)) {
                 if (sb.length() > 0) {
                     sb.append(". ");
Index: /trunk/test/unit/org/openstreetmap/josm/tools/ExceptionUtilTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/tools/ExceptionUtilTest.java	(revision 15084)
+++ /trunk/test/unit/org/openstreetmap/josm/tools/ExceptionUtilTest.java	(revision 15085)
@@ -165,9 +165,15 @@
                 "'The server replied an error with code 0.'</html>",
                 ExceptionUtil.explainFailedAuthorisation(new OsmApiException("")));
-        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:<br>'header (Code=403)'</html>",
+        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:<br>"+
+                "'header (Code=403)'</html>",
                 ExceptionUtil.explainFailedAuthorisation(new OsmApiException(HttpURLConnection.HTTP_FORBIDDEN, "header", null)));
-        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:<br>'header. body (Code=403)'</html>",
+        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:"+
+                "<br>'header. body (Code=403)'</html>",
                 ExceptionUtil.explainFailedAuthorisation(new OsmApiException(HttpURLConnection.HTTP_FORBIDDEN, "header", "body")));
-        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:<br>'body (Code=403)'</html>",
+        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:"+
+                "<br>'header_body (Code=403)'</html>",
+                ExceptionUtil.explainFailedAuthorisation(new OsmApiException(HttpURLConnection.HTTP_FORBIDDEN, "header_body", "header_body")));
+        assertEquals("<html>Authorisation at the OSM server failed.<br>The server reported the following error:<br>"+
+                "'body (Code=403)'</html>",
                 ExceptionUtil.explainFailedAuthorisation(new OsmApiException(HttpURLConnection.HTTP_FORBIDDEN, null, "body")));
     }
