fix

iOSClient/Main/CCMain.m

@@ -4001,7 +4001,7 @@
                                     handler:^(AHKActionSheet *as) {
                                         
                                         dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
-                                            [app.endToEndInterface markEndToEndFolderEncrypted:self.serverUrl fileID:_metadata.fileID token:@""];
+                                            [app.endToEndInterface markEndToEndFolderEncrypted:self.serverUrl fileID:_metadata.fileID token:nil];
                                         });
                                     }];
         }

iOSClient/Security/NCEntoToEndInterface.swift

@@ -340,7 +340,7 @@ class NCEntoToEndInterface : NSObject, OCNetworkingDelegate  {
     // MARK: Mark/Delete Encrypted Folder
     // --------------------------------------------------------------------------------------------
     
-    @objc func markEndToEndFolderEncrypted(_ serverUrl: String, fileID: String, token: String) {
+    @objc func markEndToEndFolderEncrypted(_ serverUrl: String, fileID: String, token: String?) {
         
         let token = NCNetworkingSync.sharedManager().lockEnd(toEndFolderEncrypted: appDelegate.activeUser, userID: appDelegate.activeUserID, password: appDelegate.activePassword, serverUrl: serverUrl , fileID: fileID, token: token)