diff --git a/extensions/wikidata/src/org/openrefine/wikidata/commands/ConnectionManager.java b/extensions/wikidata/src/org/openrefine/wikidata/commands/ConnectionManager.java
index c66ad6778..7f5827471 100644
--- a/extensions/wikidata/src/org/openrefine/wikidata/commands/ConnectionManager.java
+++ b/extensions/wikidata/src/org/openrefine/wikidata/commands/ConnectionManager.java
@@ -190,8 +190,15 @@ public class ConnectionManager {
             try {
                 connection.logout();
                 connection = null;
-            } catch (IOException | MediaWikiApiErrorException e) {
+            } catch (IOException e) {
                 logger.error(e.getMessage());
+            } catch (MediaWikiApiErrorException e) {
+                if ("assertuserfailed".equals(e.getErrorCode())) {
+                    // it turns out we were already logged out
+                    connection = null;
+                } else {
+                    logger.error(e.getMessage());
+                }
             }
         }
     }
diff --git a/extensions/wikidata/tests/src/org/openrefine/wikidata/commands/LoginCommandTest.java b/extensions/wikidata/tests/src/org/openrefine/wikidata/commands/LoginCommandTest.java
index 070772864..9957fbdcb 100644
--- a/extensions/wikidata/tests/src/org/openrefine/wikidata/commands/LoginCommandTest.java
+++ b/extensions/wikidata/tests/src/org/openrefine/wikidata/commands/LoginCommandTest.java
@@ -435,6 +435,33 @@ public class LoginCommandTest extends CommandTest {
         assertTrue(ConnectionManager.getInstance().isLoggedIn());
     }
 
+    @Test
+    public void testLogoutFailedBecauseCredentialsExpired() throws Exception {
+        // if our credentials expire and we try to log out,
+        // we should consider that the logout succeeded.
+        // Workaround for https://github.com/Wikidata/Wikidata-Toolkit/issues/511
+        BasicApiConnection connection = mock(BasicApiConnection.class);
+        whenNew(BasicApiConnection.class).withAnyArguments().thenReturn(connection);
+        when(connection.getCurrentUser()).thenReturn(username);
+
+        when(request.getParameter("csrf_token")).thenReturn(Command.csrfFactory.getFreshToken());
+        when(request.getParameter(USERNAME)).thenReturn(username);
+        when(request.getParameter(PASSWORD)).thenReturn(password);
+
+        // login first
+        command.doPost(request, response);
+
+        assertTrue(ConnectionManager.getInstance().isLoggedIn());
+
+        // logout
+        when(request.getParameter("logout")).thenReturn("true");
+        doThrow(new MediaWikiApiErrorException("assertuserfailed", "No longer logged in")).when(connection).logout();
+        command.doPost(request, response);
+
+        // not logged in anymore
+        assertFalse(ConnectionManager.getInstance().isLoggedIn());
+    }
+
     private static Cookie[] makeRequestCookies() {
         List<Cookie> cookies = new ArrayList<>();
         cookieMap.forEach((key, value) -> cookies.add(new Cookie(WIKIDATA_COOKIE_PREFIX + key, value)));