Solved Upload attachments: Button [+ Add Files...] not working

In my forum users are unable to add attachments to their message. The Button [+ Add Files...] has no effect at all. Drag & Drop files does not work either. When I use the browser's resfresh button, the [+ Add Files...] button's colour changes for half a second and seems to be active. If you manage to click within this very short timerange, the file upload dialogue opens. But if you do not, after half a second the button becomes grayed and is inactive.


Same issue with a clean install on a test website.
Joomla 4.2.3
PHP 8.1.11
Kunena 6.0.3

The SCeditor is not yet fully integrated, and you cannot use it to insert images into messages. Please use the CKEditor if you want to have images in messages.

Ok, I switched back to CKeditor. But the button [+ Add Files...] is still not working. The same with [You can drop files here or use the add files button.] It is not possible to upload any file. Is there an option to disable/enable this feature?

There may be several reasons for this. There are a lot of scripts running on your site, so there can be conflicts. But also CSS conflicts are possible. Therefore you have to find out what is causing this error. That was also the reason for the question, if this error also occurs with the Joomla default template Cassiopeia.

With Cassiopeia we have the same issue. In Global Config I enabled «Error reporting» and set it to «Maximum», but there seem to be no errors. Nevertheless I began to disable one component after the other and I found one that is obviously causing this issue. I will have to configure it somehow in order to prevent it from
causing conflicts with Kunena.

Thank you for your patience. This issue can be marked as resolved.

you write
"Nevertheless I began to disable one component after the other and I found one that is obviously causing this issue."
can you also tell us which one that is/was so that others with a similar problem may also benefit from it