When user has no access to page 'foo' (or isn't logged in), and this page is a part of URL (..id=foo..) and then, he clicks on 'Send new password', instead of resending password page, he gets Access Denied. Why? I think, that Dokuwiki first checks if user (or anonymous not logged user) has access to the page, if not, it just displays information 'Access Denied' even if user just want to resend his password. If all wiki pages are restricted to view for registered users only, it is not possible to resend users passwords.
Simpliest solution: find line below in file 'inc/html.php':
print ': <a href="'.wl($ID,'do=resendpwd').'" class="wikilink1">'.$lang['btn_resendpwd'].'</a>';
..and replace it by:
print ': <a href="'.wl('','do=resendpwd').'" class="wikilink1">'.$lang['btn_resendpwd'].'</a>';
You also have to grant access to read for all users for Your startup page. For example in file 'acl.auth.php' if Your startup page is called 'start' You must have:
start @ALL 1
But I think, that is better way to solve the problem, so I'm reporting this situation as BUG.