In rtfm Skeleton right page not found

I have edited/deleted the main/first page. Now there is the 404 error if I call my Webpage first.
If I click on the left site it is working.
Any idea what the reason is?
How could I get the original behavior that the first Topic on the left is shown at the right.

Thanks in advance

— yaml
alias: ‘/blog’

In System.yaml
Here, specify the path to your first page.

Thanks for the hint. Directly edit the custom path did not work. But due to the use of the admin plugin within the rftm Skeleton I stored again the configugartion in the admin plugin. This was working.