Image content title, client name, assigned task and a text editor, It's not enough to guess why the edit content is not working.
Do you have check the Drupal error log and server error log, what they display, I need to know, it will help me to understand the reason for the issue.
Please tell me when this issue starts. I suspect it will come because of an internal upgrade of any Drupal module like I face the same issue in one of my previous projects when client mistake upgrades the WYSIWYG module and after that, no new content was created because of WYSIWYG editor is not working properly.
Oh, one minute, Please tell me, are you able to create the new content. and is this issue is only for the specific content type or for all, this information will help me to short out the issue.
I am ready to start work on the issue immediately,
Please take the backup of the database and codebase.
And provide me the access, so I can start working.
But If you have a problem to share access right know,
then no problem, Please share your screen.
I will investigate your site from TeamViewer and tell you what is the reason for this issue.
I hope you will agree with this method.
Please ping me at your time or feel free to call me.
Thank You