I think i'm having the same exact issue.

you might need to rerun your update.  Read this fully before you do anything, if you do not understand any of it then wait for ross.  You might be able to rerun the update by just running it without downloading it again.  But if you are not sure then wait for ross please.  We dont want to make the issue worse than it is. 

https://developers.oxwall.com/forum/topic/44433

This may not be your version but it should give you an idea.  

the update pack for 1.8.3 can be found here   https://developers.oxwall.com/download

Didn't work.

Tiant, please hit ctrl+u on your index page and provide screenshot of your source code page. That how I found out Daniel did not upgrade successfully. 

no index page of Oxwall software screenshot, not your Cpanel file manager

right click select view source works too 

You're using free hosting, most of them does not meet our requirements. Please check them and make sure your server does: http://www.oxwall.org/hosting

I tried to register at your website and opened console and it throws a lot of 500 internal server error, almost to every action.