Question Links to Attached PDF's all lead to 404 Page

Database collation check: The collation of your table fields are correct

Joomla! SEF: Enabled | Joomla! SEF rewrite: Enabled | FTP layer: Disabled |

This message contains confidential information

htaccess: Exists | PHP environment: Max execution time: 30 seconds | Max execution memory: 100M | Max file upload: 50M

Kunena menu details:

Warning: Spoiler!

ID	Name	Menutype	Link	Path	In trash
173	Forum	mainmenu	Itemid=164	kunena-2014-07-06	No
164	Forum	kunenamenu	view=home&defaultmenu=166	forum	No
165	Index	kunenamenu	view=category&layout=list	forum/index	No
166	Recent Topics	kunenamenu	view=topics&mode=replies	forum/recent	No
167	New Topic	kunenamenu	view=topic&layout=create	forum/newtopic	No
168	No Replies	kunenamenu	view=topics&mode=noreplies	forum/noreplies	No
169	My Topics	kunenamenu	view=topics&layout=user&mode=default	forum/mylatest	No
170	Profile	kunenamenu	view=user	forum/profile	No
171	Help	kunenamenu	view=misc	forum/help	No
181	Forum	rotate-top	view=topics&layout=posts&mode=recent	forum-posts	Yes
1277	mobile_kunena	mobile-menu	view=home&defaultmenu=164	mobile-kunena	No

Joomla default template details : J51_Letterpress | author: Joomla51 | version: 1.2 | creationdate: June 2013

Kunena default template details : Crypsis | author: Kunena Team | version: 5.1.1 | creationdate: 2018-06-10

Kunena template params:

Warning: Spoiler!

DefaultCategoryicon	icon-folder
profileIconset	default
DefaultIconset	default
editorIconset	default
lightboxColor	white
bootstrap	0
borderless	0
SubjectLengthMessage	80
fullactions	1
quick	0
displayMenu	1
displayModule	1
displayBreadcrumb	1
displayAnnouncement	1
displayFooter	1
avatarPosition	left
avatarType	none
labels	0
whoisonlineName	default
formRecover	0
topicicontype	0
fontawesome	0
socialshare	0
socialtheme	classic
writeaccess	0
video	1
maps	1
emoticons	1
twitter	1
ebay	1
link	1
picture	1
hide	1
spoiler	1
table	1
code	1
quote	1
divider	1
instagram	1
soundcloud	1
confidential	1
hr	1
listitem	1
supscript	1
subscript	1
numericlist	1
bulletedlist	1
alignright	1
alignleft	1
center	1
underline	1
italic	1
bold	1
strikethrough	1
colors	1
size	1
IconColor	inherit
IconColorNew	#48a348
avatarSizeX	40
avatarSizeY	90
avatarSizeXThumb	36
avatarSizeYThumb	36
avatarSizeXWelcome	72
avatarSizeYWelcome	72
avatarSizeXList	36
avatarSizeYList	36
avatarSizeXPost	144
avatarSizeYPost	144
avatarSizeXProfile	200
avatarSizeYProfile	200
icomoon	1
tooltips	1
displayDropdownMenu	1
displayDropdownContent	1
socialsharetag
optional_username	0
localstorage	0
editor	0
wysibb
templatebyText
templatebyName
templatebyLink

Kunena version detailed: Kunena 5.1.1 | 2018-06-10 [ Belinda ]
| Kunena detailed configuration:

Warning: Spoiler!

Kunena config settings:
board_offline	0
enablerss	1
threads_per_page	20
messages_per_page	10
messages_per_page_search	15
showhistory	1
historylimit	6
shownew	0
disemoticons	0
template	crypsis
showannouncement	1
avataroncat	0
catimagepath	category_images
showchildcaticon	1
rtewidth	450
rteheight	300
enableforumjump	1
reportmsg	1
username	0
askemail	0
showemail	0
showuserstats	1
showkarma	1
useredit	1
useredittime	0
useredittimegrace	600
editmarkup	1
allowsubscriptions	1
subscriptionschecked	1
allowfavorites	1
maxsubject	50
maxsig	300
regonly	0
pubwrite	0
floodprotection	0
mailmod	1
mailadmin	1
captcha	0
mailfull	1
allowavatarupload	1
allowavatargallery	1
avatarquality	75
avatarsize	2048
imageheight	800
imagewidth	800
imagesize	10000
filetypes	txt,rtf,pdf,zip,tar.gz,tgz,tar.bz2,mp4
filesize	10000
showranking	1
rankimages	1
userlist_rows	30
userlist_online	1
userlist_avatar	1
userlist_posts	1
userlist_karma	1
userlist_email	0
userlist_joindate	1
userlist_lastvisitdate	1
userlist_userhits	1
latestcategory
showstats	1
showwhoisonline	1
showgenstats	1
showpopuserstats	1
popusercount	5
showpopsubjectstats	1
popsubjectcount	5
showspoilertag	1
showvideotag	1
showebaytag	1
trimlongurls	1
trimlongurlsfront	40
trimlongurlsback	20
autoembedyoutube	1
autoembedebay	1
ebaylanguagecode	en-us
sessiontimeout	1800
highlightcode	0
rss_type	topic
rss_timelimit	month
rss_limit	100
rss_included_categories
rss_excluded_categories
rss_specification	rss2.0
rss_allow_html	1
rss_author_format	name
rss_author_in_title	1
rss_word_count	0
rss_old_titles	1
rss_cache	900
defaultpage	recent
default_sort	asc
sef	1
showimgforguest	1
showfileforguest	1
pollnboptions	4
pollallowvoteone	1
pollenabled	1
poppollscount	5
showpoppollstats	1
polltimebtvotes	00:15:00
pollnbvotesbyuser	100
pollresultsuserslist	1
maxpersotext	50
ordering_system	mesid
post_dateformat	ago
post_dateformat_hover	datetime
hide_ip	1
imagetypes	jpg,jpeg,gif,png
checkmimetypes	1
imagemimetypes	image/jpeg,image/jpg,image/gif,image/png
imagequality	50
thumbheight	32
thumbwidth	32
hideuserprofileinfo	put_empty
boxghostmessage	0
userdeletetmessage	2
latestcategory_in	1
topicicons	1
debug	0
catsautosubscribed	0
showbannedreason	0
showthankyou	1
showpopthankyoustats	1
popthankscount	5
mod_see_deleted	0
bbcode_img_secure	text
listcat_show_moderators	1
lightbox	1
show_list_time	8760
show_session_type	0
show_session_starttime	0
userlist_allowed	1
userlist_count_users	2
enable_threaded_layouts	0
category_subscriptions	post
topic_subscriptions	every
pubprofile	1
thankyou_max	10
email_recipient_count	0
email_recipient_privacy	bcc
captcha_post_limit	0
image_upload	registered
file_upload	registered
topic_layout	flat
time_to_create_page	1
show_imgfiles_manage_profile	1
hold_newusers_posts	1
hold_guest_posts	0
attachment_limit	20
pickup_category	0
article_display	intro
send_emails	1
fallback_english	1
cache	1
cache_time	60
iptracking	1
rss_feedburner_url
autolink	1
access_component	1
statslink_allowed	1
superadmin_userlist	0
legacy_urls	1
attachment_protection	0
categoryicons	1
avatarresizemethod	1
avatarcrop	0
user_report	1
searchtime	365
teaser	0
ebay_language	0
allow_change_subject	1
max_links	10
read_only	0
ratingenabled	0
url_subject_topic	0
log_moderation	0
attach_start	0
attach_end	14
attachment_utf8	1
autoembedsoundcloud	1
emailheader	/media/kunena/email/hero-wide.png
user_status	1
signature	1
personal	1
social	1
plain_email	0
moderator_permdelete	0
avatartypes	gif, jpeg, jpg, png
smartlinking	0
defaultavatar	nophoto.png
defaultavatarsmall	s_nophoto.png
quickreply	1
avataredit	0
activemenuitem
mainmenu_id
home_id
index_id
moderators_id
topiclist_id
misc_id
profile_id
search_id
avatar_type	1
sef_redirect	1
allow_edit_poll	1
recaptcha_publickey
recaptcha_privatekey
recaptcha_theme	white
keywords	0
userkeywords	0
userlist_name	1
usernamechange	1
version_check	1

| Kunena integration settings:

Warning: Spoiler!

Kunena - Finder Disabled
Kunena - AltaUserPoints Disabled
Kunena - Community Builder Disabled
Kunena - Easyblog Disabled
Kunena - Easyprofile Disabled
Kunena - Easysocial Enabled: login=1 activity=1 avatar=1 profile=1 private=1 activity_badge_limit=0 activity_points_limit=0
Kunena - Gravatar Disabled
Kunena - JomSocial Disabled
Kunena - Joomla Enabled: access=1 login=1
Kunena - Kunena Enabled: avatar=1 profile=1
Kunena - UddeIM Disabled

| Joomla! detailed language files installed:

Warning: Spoiler!

Joomla! languages installed:
en-GB	English (en-GB)

Third-party components: None

Third-party SEF components: None

Plugins: Search - Kunena Search 5.1.0

Modules: Kunena Latest 5.1.0 | Kunena Stats 5.1.0 | Kunena Login 5.1.0 | Kunena Search 5.1.0

I'm not sure what update caused my PDF links to all fail. To rule out a server change (year+ ago) I added a new PDF attachment to a post.
Same fault.
Files are present in Kunena media attachments file on server.

This browser does not support PDFs. Please download the PDF to view it: Download PDF.
The above is the message displayed on any post with a PDF. To verify the problem is not browser related, I tried with several browsers on both Linux and Windows Computers.
A post from years ago is an example, rotate.aero/forum/ata-24-electrical-gene...aircraft-power-pdf#7
I deleted the old file and reinserted a new one....... same results.

This bug is already fixed. You can install Kunena nightly build or you change one line in the pdf.php

Path is /components/com_kunena/template/system/layouts/bbcode/attachment/pdf.php

Change the line 16
from to
github.com/Kunena/Kunena-Forum/commit/ab...8f8b690c7e4a63a53f6f

Problem solved..... Thank you.

Is it possible that this bug occurs again?
I use Kunena 5.1.8 with Blue Eagle 1.5.2 and in /components/com_kunena/template/system/layouts/bbcode/attachment/pdf.php the correct code

Configuration - uploads: Protect attachments
I can choose an attachment.
attachment is also placed.
However, the function of inserting the attachment into the text gives the message:
This browser does not support PDFs. Please download the PDF to view it: Download PDF.

Can there be another cause besides the above fix?

I'm sorry, but this bug still exists. If you allow pdf, it's not possible to use the option protect attachments. It breaks the pdfs.