The php page of the website can be opened. Why can't html and txt be opened? Css and js Open normally

The php page of the website can be opened. Why can't html and txt be opened? When css and js are enabled in the normal lnmpa environment, Firefox prompts:

The php page of the website can be opened. Why can't html and txt be opened? Css and js Open normally
Lnmpa environment

Firefox prompts:

Reply content:

The php page of the website can be opened. Why can't html and txt be opened? Css and js Open normally
Lnmpa environment

Firefox prompts:

First, check whether the url is wrong, check whether the file exists, and then check the permission. (in fact, the simplest thing is to directly view the server log)

It may be Redirected because css and js resources are static resources, so they are not redirected.
If the server is apache, check. Htaccess.Html,TxtAdd