Hey there,
I am really sorry for the delay of this reply as it is a weekend for us here.
It seems work fine for me when i try to submit a new test post from your frontend, you can check my video here :
http://take.ms/Hzfbcj
Am i missing some of the step reproduce this issue?
By the way, I also realised your backend hitting this following error :
0 Could not json decode the token
I believe some of the user data do not store correctly with the JSON format from your database but i do not know is it related with this issue yet.
Perhaps you can provide us with your FTP access and which user account you trying to submit a blog post on the site?