Menu's in Muse

[#1]

I haven't used Muse since 2017, and an old client wanted to revise a website I did a while back. I added a new page, but it is not showing up in the menu. As I remember, when you added a page in the thumbnail it automatically added it to the menu. Has something changed? I have the lastest version of Muse via the Creative Cloud.

[#2]

With me happens to export the entire site and fail to display the page "WHO ARE" - only this page, the others appear normally. It also gives an error in In-Browser Editing saying that the editor could not read the website Manifest file sent on the FTP host. Why is it that only my child page "ABOUT US" cannot be loaded after export and gives ERROR 404 (not found)?

[#3]

@stevebruem: No, nothing has changed in this respect. Perhaps the menu widget is set to "manual".

@BrazilMuse: Your issue isn't related to this one. Please stick to your other thread.