diff --git a/src/java/davmail/http/DavGatewayHttpClientFacade.java b/src/java/davmail/http/DavGatewayHttpClientFacade.java
index c83e02ce..a38bd587 100644
--- a/src/java/davmail/http/DavGatewayHttpClientFacade.java
+++ b/src/java/davmail/http/DavGatewayHttpClientFacade.java
@@ -76,6 +76,8 @@ public final class DavGatewayHttpClientFacade {
         // register custom cookie policy
         CookiePolicy.registerCookieSpec("DavMailCookieSpec", DavMailCookieSpec.class);
 
+        AuthPolicy.registerAuthScheme(AuthPolicy.BASIC, LenientBasicScheme.class);
+
     }
 
 
diff --git a/src/java/davmail/http/LenientBasicScheme.java b/src/java/davmail/http/LenientBasicScheme.java
new file mode 100644
index 00000000..95bc204c
--- /dev/null
+++ b/src/java/davmail/http/LenientBasicScheme.java
@@ -0,0 +1,36 @@
+/*
+ * DavMail POP/IMAP/SMTP/CalDav/LDAP Exchange Gateway
+ * Copyright (C) 2011  Mickael Guessant
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package davmail.http;
+
+import org.apache.commons.httpclient.auth.BasicScheme;
+import org.apache.commons.httpclient.auth.MalformedChallengeException;
+
+/**
+ * Workaround for broken servers that send invalid Basic authentication challenge.
+ */
+public class LenientBasicScheme extends BasicScheme {
+    public void processChallenge(String challenge)
+            throws MalformedChallengeException {
+        if ("Basic".equalsIgnoreCase(challenge)) {
+            super.processChallenge("Basic \"default\"");
+        } else {
+            super.processChallenge(challenge);
+        }
+    }
+}