I am using org-mode to write notes and org-agenda to organize all notes, especially to search some info. by keyword or tag.

C-c a m can search some files by tag inputed, C-c a s by keyword ,those functions from org-agenda are well to utilize, however, I need to add org-file into the agenda-list by hand.

I added some codes into .emacs, such as 

(setq org-agenda-files (list "path/folder/*.org"))

or 

(setq org-agenda-files (file-expand-wildcards "path/folder/*.org"))

but, both failed to add files under the folder specified into agenda-list automatically, so I can't search keyword or tag among those org-files, unless that I open a org-file and type C-c [ to add it into agenda-list.

How can I make all org-files under a folder automatically added in agenda?

emacs org-mode
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