Solved Error after upgrading Kunena

Thanks for the tip! I found the report, this is from my life site (with older version of kunena):

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: 60 seconds | Max execution memory: 256M | Max file upload: 64M

Kunena menu details:

Warning: Spoiler!

ID	Name	Menutype	Link	Path	In trash
1159	Forum actief	side-menu	view=category&layout=list&catid=0	forum-actief	No
3688	Forum actief	intranet-menu	view=category&layout=list&catid=0	forum-actief-2	No

Joomla default template details : rt_notio | author: RocketTheme, LLC | version: 1.1.1 | creationdate: November 2, 2017

Kunena default template details : Crypsisb3 | author: Kunena Team | version: 5.0.14 | creationdate: 2018-03-14

Kunena template params:

Warning: Spoiler!

DefaultCategoryicon
profileIconset	default
DefaultIconset	default
editorIconset	default
lightboxColor	white
borderless	1
tooltips	1
SubjectLengthMessage	80
fullactions	1
quick	0
displayMenu	1
displayDropdownMenu	1
displayDropdownContent	1
displayModule	1
displayBreadcrumb	1
displayAnnouncement	1
displayFooter	1
avatarPosition	left
formRecover	0
labels	0
whoisonlineName	default
avatarType	img-rounded
topicicontype	B3
fontawesome	0
icons	0
socialshare	0
socialsharetag
socialtheme	classic
writeaccess	0
localstorage	0
IconColor	inherit
IconColorNew	#48a348
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
avatarSizeX	40
avatarSizeY	90
avatarSizeXThumb	36
avatarSizeYThumb	36
avatarSizeXWelcome	72
avatarSizeYWelcome	72
avatarSizeXList	36
avatarSizeYList	36
avatarSizeXPost	144
avatarSizeYPost	144
avatarSizeXProfile	200
avatarSizeYProfile	200
templatebyText
templatebyName
templatebyLink

Kunena version detailed: Kunena 5.0.14 | 2018-03-14 [ Stephen Hawking ]
| Kunena detailed configuration:

Warning: Spoiler!

Kunena config settings:
board_offline	0
enablerss	1
threads_per_page	20
messages_per_page	6
messages_per_page_search	15
showhistory	1
historylimit	6
shownew	1
disemoticons	0
template	crypsisb3
showannouncement	1
avataroncat	0
catimagepath	category_images
showchildcaticon	1
rtewidth	450
rteheight	300
enableforumjump	1
reportmsg	1
username	1
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	1
pubwrite	0
floodprotection	0
mailmod	0
mailadmin	0
captcha	0
mailfull	1
allowavatarupload	1
allowavatargallery	1
avatarquality	75
avatarsize	2048
imageheight	800
imagewidth	800
imagesize	1500
filetypes	txt,rtf,pdf,zip,tar.gz,tgz,tar.bz2
filesize	2000
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	0
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	0
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	720
show_session_type	0
show_session_starttime	0
userlist_allowed	1
userlist_count_users	1
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	0
hold_guest_posts	0
attachment_limit	8
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	6
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
plain_email	0
moderator_permdelete	0
signature	1
personal	1
social	1
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
recaptcha_publickey
recaptcha_privatekey
recaptcha_theme	white
keywords	0
userkeywords	0
userlist_name	1
usernamechange	0
version_check	1

| Kunena integration settings:

Warning: Spoiler!

Kunena - Finder Disabled
Kunena - AlphaUserPoints Disabled
Kunena - AltaUserPoints Disabled
Kunena - Community Builder Disabled
Kunena - Easyblog Disabled
Kunena - Easyprofile Disabled
Kunena - Easysocial Disabled
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)
nl-NL	Dutch (nl-NL)

Third-party components: None

Third-party SEF components: None

Plugins: None

Modules: None

And this is from my test site, with kunena upgraded and not working:

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: 60 seconds | Max execution memory: 256M | Max file upload: 64M

Kunena menu details:

Warning: Spoiler!

ID	Name	Menutype	Link	Path	In trash
1159	Forum actief	side-menu	view=category&layout=list&catid=0	forum-actief	No
3688	Forum actief	intranet-menu	view=category&layout=list&catid=0	forum-actief-2	No

Joomla default template details : rt_notio | author: RocketTheme, LLC | version: 1.1.1 | creationdate: November 2, 2017

Kunena default template details : Crypsis | author: Kunena Team | version: 5.1.3 | creationdate: 2018-08-19

Kunena template params:

Warning: Spoiler!

DefaultCategoryicon
profileIconset	default
DefaultIconset	default
editorIconset	default
bootstrap	1
icomoon	1
tooltips	1
borderless	1
SubjectLengthMessage	80
fullactions	1
quick	0
displayMenu	1
displayDropdownMenu	1
displayDropdownContent	1
displayModule	1
displayBreadcrumb	1
displayAnnouncement	1
displayFooter	1
avatarPosition	left
avatarType	img-circle
labels	0
whoisonlineName	default
formRecover	0
topicicontype	B2
fontawesome	0
socialshare	0
socialsharetag
socialtheme	classic
optional_username	0
writeaccess	0
localstorage	0
IconColor	inherit
IconColorNew	#48a348
editor	0
video	0
maps	0
emoticons	1
twitter	0
ebay	0
link	1
picture	1
hide	1
spoiler	0
table	1
code	0
quote	1
divider	1
instagram	0
soundcloud	0
confidential	0
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
wysibb	bold,italic,underline,strike,sup,sub,justifyleft,justifycenter,justifyright,|,img,link,|,bullist,numlist,|,fontcolor,fontsize,fontfamily,|,quote,table,removeFormat
avatarSizeX	40
avatarSizeY	90
avatarSizeXThumb	36
avatarSizeYThumb	36
avatarSizeXWelcome	72
avatarSizeYWelcome	72
avatarSizeXList	36
avatarSizeYList	36
avatarSizeXPost	144
avatarSizeYPost	144
avatarSizeXProfile	200
avatarSizeYProfile	200
templatebyText
templatebyName
templatebyLink

Kunena version detailed: Kunena 5.1.3 | 2018-08-19 [ Dione ]
| Kunena detailed configuration:

Warning: Spoiler!

Kunena config settings:
board_offline	0
enablerss	1
threads_per_page	20
messages_per_page	6
messages_per_page_search	15
showhistory	1
historylimit	6
shownew	1
disemoticons	0
template	crypsis
showannouncement	1
avataroncat	0
catimagepath	category_images
showchildcaticon	1
rtewidth	450
rteheight	300
enableforumjump	1
reportmsg	1
username	1
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	1
pubwrite	0
floodprotection	0
mailmod	0
mailadmin	0
captcha	0
mailfull	1
allowavatarupload	1
allowavatargallery	1
avatarquality	75
avatarsize	2048
imageheight	800
imagewidth	800
imagesize	1500
filetypes	txt,rtf,pdf,zip,tar.gz,tgz,tar.bz2
filesize	2000
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	0
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	0
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	720
show_session_type	0
show_session_starttime	0
userlist_allowed	1
userlist_count_users	1
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	0
hold_guest_posts	0
attachment_limit	8
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	6
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
use_system_emails	0
autoembedinstagram	1
recaptcha_publickey
recaptcha_privatekey
recaptcha_theme	white
keywords	0
userkeywords	0
userlist_name	1
usernamechange	0
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 Disabled
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)
nl-NL	Dutch (nl-NL)

Third-party components: None

Third-party SEF components: None

Plugins: None

Modules: None

It lacks your Kunena menu. Kunena requires an undestroyed Kunena menu.. If it does not correctly exist, then these errors occur. Repair your Kunena menu items, then it should all work.
Please see also here

Thanks for your answer! This helped and it's now working fine again!

Best wishes, Rita