Your site is still running on Elgg 1.8. How often it was suggested that you upgrade to a newer (and still supported version of Elgg)? I don't know what could be the problem. What have you changed that caused the problem? Is it even CKEditor? Elgg 1.8 came with the Tinymce plugin and not CKEditor. Is it the Elgg core plugin causing the problem or is it a 3rd party plugin providing the CKeditor? In the latter case: update your site is probably the only solution because I doubt that anyone would still make any bugfixing for Elgg 1.8. If you use the Tinymce plugin that came with Elgg 1.8 and this plugin stopped working (again: have you changed anything causing the problem?) you could try my Extended Tinymce plugin from https://elgg.org/plugins/782028. The version for Elgg 1.8 is also already 5 years old but it should at least contain a newer version of the underlying Tinymce editor that might work a bit better.