IOS Facebook invite Missing App Link URL

Question

enter image description here

I get the url “h t t p s :// fb . me / number” by App Link Tool which is reference to the https://developers.facebook.com/docs/app-invites/ios?locale=en_US.

And use the code

FBSDKAppInviteContent *content =[[FBSDKAppInviteContent alloc] init];

content.appLinkURL = [NSURL URLWithString:@"h t t p s :// fb . me / number"];

content.appInvitePreviewImageURL = [NSURL URLWithString:@"https ://xxxx_image.jpg"];

[FBSDKAppInviteDialog showFromViewController:self
                                 withContent:content
                                    delegate:self];

But it always said "Missing App Link URL",I have no way.

Can any one give some advice?