Kunena - Community Builder Integration: New Message Preview Text Broken

I know this issue has been asked before on both the CB and Kunena forums, but I have not found a real solution yet and am hoping you might have come across a fix, since you use Kunena on the Joomlapolis website.

I have an long-time established website with Community Builder and Kunena Forum integrated very nicely, but when you compose a new topic or reply on the Kunena forum, the PREVIEW box does not work. It is just blank (please see attached screenshot).

When I disable the Kunena - Community Builder Integration plugin the Preview box works fine.

This problem began when I performed a major upgrade (Joomla, CB, Kunena, and changed template). I have almost 10,000 registered CB users, so moving forward without the CB-Kunena integration is not an option for me.

Joomla 3.6.5
Community Builder 2.1.0
Kunena 5.0.5
K2 2.7.1

Thank you!

Works perfectly fine here. It typically fails due to the ajax response having something other than JSON on it. It could be any number of things doing this from a 3rd party extension or a 3rd party CB plugin or an auto action in CB Auto Actions configured to output something. You'll need to press F12 to open your browsers developer console then under the Network tab you'll see the HTTP request for the preview. You should be able to review its response to see what it responded with.

Thank you for the reply.

Here is the results of the Developer Tools Console when I click the PREVIEW button. Does this mean that is a JQuery problem?

jquery-migrate.min.js:2:542
JQMIGRATE: Migrate is installed, version 1.4.1 jquery-migrate.min.js:2:542

jquery.min.js:4:26272
Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience. For more help xhr.spec.whatwg.org/ jquery.min.js:4:26272

send @ jquery.min.js:4
ajax @ jquery.min.js:4
kPreviewHelper @ edit.js:17
(anonymous) @ edit.js:43
dispatch @ jquery.min.js:3
r.handle @ jquery.min.js:3

jquery.min.js:2:24932
Empty string passed to getElementById().

- - - -

Here are the results I get when I look at the console for the Joomlapolis Forum when I hit the Preview button:

jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:12739
JQMIGRATE: Migrate is installed with logging active, version 1.4.1

jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:6
Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check xhr.spec.whatwg.org/ .

send @ jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:6
ajax @ jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:6
kPreviewHelper @ jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:8707
(anonymous) @ jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:8733
dispatch @ jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:5
r.handle @ jscss.php?f=c384019…&type=js&gz=gz&d=1&i=0:5

The console is not going to help you debug this. You need to monitor the ajax HTTP request under the Network tab. Once it's done you can click the request and it'll give you details regarding it. Including what it responded with.

I resolved this issue for my installation. Hopefully the EASY fix I came across will be helpful to others.

Under GLOBAL CONFIGURATION > SYSTEM tab, I had the CACHE SETTINGS set to "OFF - CACHING DISABLED". When I changed it to "ON - CONSERVATIVE CACHING" the Preview functionality started working.

I cleared the cache and purged expired as well.

Thanks for your help with this issue.

Strange that caching would fix it, but thank you for providing your solution. It's worth noting if anyone has ajax calls failing like that it's almost guaranteed to be something installed that is outputting HTML during format=raw or format=json. CB was at some point, but we've since fixed our output to respect format=json (we've always respected format=raw).