FOS休息 - 生产环境问题

I have an application, which use SF2, FOS-RestBundle, MySQL, AngularJS. Symfony is being used just to provide REST API for my frontend application written in Angular. Everything works great when I have debug mode enabled and my API urls are like:

"HOST/app_dev.php/api/users"

But when I switch to production environment and change my urls to:

"HOST/api/users"

I keep getting such an error:

{"error":{"code":500,"message":"Internal Server Error"}}

This is my FOSRest configuration (and sensio framework):

sensio_framework_extra:
view: { annotations: false }
router: { annotations: true }
request: { converters: true }

fos_rest:
routing_loader:
    default_format: json
    include_format: true
param_fetcher_listener: force
body_listener: true
allowed_methods_listener: true
view:
    view_response_listener: 'force'
    formats:
        json: true
format_listener:
    rules:
        - { path: '^/api', priorities: ['json', 'xml'], fallback_format: null, prefer_extension: true }
        - { path: '^/', priorities: [ 'text/html', '*/*'], fallback_format: null, prefer_extension: true }
access_denied_listener:
    json: true

I know, that error is triggered somewhere in FOSRestBundle, but I have a 'breakpoint' in ExceptionController. It does not even go there.

Screenshot of error and headers

Appreciate any help.

When I figured out how to get to server logs in my hosting I found a following error:

Your data could not be encoded because it contains invalid UTF8 characters." at app/endor/jms/serializer/src/JMS/Serializer/JsonSerializationVisitor.php line 36

And solution is here ("SET NAMES UTF8" did the trick):

JMSSerializer and UTF-8 encoding error ( Symfony2.4 )