Upgraded to 1.18.4 a few weeks ago, but haven't tried uploading images until today. Was on 1.18.1 and "think" it was working then, but not sure last time we used inline images.
I was initially getting another error, but used this thread to (https://forum.osticket.com/d/108072-1184-invalid-csrf-token-when-attaching-image/2) edit js/redactor-osticket.js.
That did fix that error. Now I'm get invalid CSRF Token, but only when editing the Knowledgebase, as far as I can tell so far.
As soon as I open the article, I get the 404 error in Developer Tools in Chrome. Once I click on the Edit button, I get another.
When I go to add a picture I get:
quest URL
https://domain.com/scp/ajax.php/draft/3398/attach
Request Method
POST
Status Code
403 Forbidden
Remote Address
xxx.xxx.xxx.xxx:443
Referrer Policy
strict-origin-when-cross-origin
When I try to add picture, it also says: Unable to save draft. Refresh the current page to restore and continue your draft.
That is when I get the above error.