Updating Failed and Publishing Failed

Website, Application, Performance
1 
Hello, my site hdcoupons.com
When I try to publish posts or pages with a lot of text (In a lot of text, I mean more than just title and a few words) in my WordPress site it shows this (Image Attached). So I basically can't upload anything to the site. 
![Resolved|690x27](upload://gWjFnDgPRq70Vu26hzOt8dcCoI5.png)
3

Hi,

Is this still affecting you? If so, please take some time to learn how to use markdown and edit your post so that only your domain name is marked as code. (If you cannot edit, reply and post the details again.)

https://commonmark.org/help/tutorial/