HOW TO FIX The Syntax Error Unexpected token when editing order in OpenCart 2
In Recent days I have encountered many reports about the Syntax Error (SyntaxError): Unexpected end of input OK when editing order in OpenCart 2. The error looks like as image below:
how to fix this problem. You can follow steps below:
1. Disable the Maintenance Mode in admin > System > Stores > Your store > tab Server.
2. Go to Admin > System > Users > API > Create new API account.
3. Go to Admin > System > Settings > Edit your store > Select tab Option > Checkout section > set API User to the created account.
4. Try to edit order again, you will see the problem is fixed.
NOTE THAT: In some specific hosting, they cause this problem too. If you follow the steps above, it will help you to fix it.
Thankyou : http://www.viethemes.com/how-to-fix-error-syntaxerror-unexpected-end-of-input-ok-when-editing-order-in-opencart-2/