Blog Posting not connecting to server

I am using WP RoundTable theme by Tomas Mackevicius but every time I write a post or blog it keep showing a message that “…Are not connect with server” and the post doesnt work. Can you please suggest me why I am unable to post on my site as user.

The details of the website: https://www.superbadpage.com

Please feel free to login and test any post to check the error.”

I would appreciate your help if you can give me a solution. I have been waiting for ages to fix it.