Hi
It depends on CPT UI settings.
Or it depends on register_post_type() Parameters.
For example…
What is the setting value of Exclude From Search in CPT UI Settings?
If the Exclude From Search setting is true, you can not search the front end for a specific post type.
Therefore the page is Not Found.
In order to display with a specific post type, the setting value of Exclude From Search should be set to false.
Refer to Code Reference for detailed settings of register_post_type().
https://developer.ww.wp.xz.cn/reference/functions/register_post_type/