Why the confluence page is disappear

[Luna]

Some confluence pages created by me, but some time later, they are disappear.

Can't trace it from the history and 

And this issue happened to some pages, but not all.

[Alex Koxaras _Relational_]

Hi @Luna  and welcome to the community,

Perhaps someone deleted the pages, or removed them, or restrict them from viewing. Have your confluence admin look at the log files.

[Fabio Racobaldo _Herzum_]

Hi @Luna ,

welcome to the Atlassian community!

Please could you check if those pages have been deleted? Look to space trash :

Restore a deleted page

When you restore a Confluence page, it will be restored to the root of the space, not to its old location. This means that it sits at the same level in the page tree as your home page, so it won't be visible to anyone from the space sidebar. You can find this page by going to Space settings and selecting Reorder from the Manage pages card. 

To restore a deleted page:

1. Select Space settings from the sidebar.

2. Select Trash from the Manage pages card.

3. Select Restore for the page you wish to restore.

If a new page has already been created in that space with the same name as the page you're restoring, you'll be given an option to rename the page before it's restored.

Fabio