Accessing my own folders in wp installation directory

Hi,

I have installed wordpress in my domain root folder (public_html). My wordpress site is working fine – so no problem with that. However, if I try to create a new folder for my gallery and stuff into public_html directory and try to access htlm-file in that directory, I get 404 error message. If I create a test html file in the root (public_html) directory I can access it, but if I create files in any subdirectory, I cannot access them. Why is this? I guess that WordPress installation somehow causes this. Perhaps I should make changes to .htaccess file, but what kind of changes?

Example:

I can view my wordpress site when I go to “address”:
https://www.mysite.com (as my wordpress is installed in the root)

I can view my test file when I go to address:
https://www.mysite.com/test.html (as my test file is saved in the root)

If I create a subfolder called “MyGallery” into my public_html folder and create test.html file in there, I cannot access the file – I just get 404 error
https://www.mysite.com/MyGallery/test.html

What should I do to see my test.html file created in a subfolder that is located in the same root as wordpress?

Cheers,

Antti