[2018-06-18 14:59:10] report.INFO: Broken reference: the 'notification.messages' tries to reorder itself towards 'user', but their parents are different: 'header.inner.right' and 'header' respectively. [] []

public function execute()
{
    try {
        $imageId = $this->_request->getParam('param_name', 'cat_head_img');

        $result = $this->imageUploader->saveFileToTmpDir($imageId);

        $result['cookie'] = [
            'name' => $this->_getSession()->getName(),
            'value' => $this->_getSession()->getSessionId(),
            'lifetime' => $this->_getSession()->getCookieLifetime(),
            'path' => $this->_getSession()->getCookiePath(),
            'domain' => $this->_getSession()->getCookieDomain(),
        ];
        return $this->resultFactory->create(ResultFactory::TYPE_JSON)->setData($result);
    } catch (Exception $e) {
        $this->logger->critical('Cat Header message', ['exception' => $e]);
    }
}

<formElements>
            <fileUploader>
                <settings>
                    <required>false</required>
                    <uploaderConfig>
                        <param xsi:type="url" name="url" path="catalog/category_header/upload"/>
                    </uploaderConfig>
                    <previewTmpl>Magento_Catalog/image-preview</previewTmpl>
                </settings>
            </fileUploader>
        </formElements>

<?xml version="1.0"?>
    <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:App/etc/routes.xsd">
        <router id="standard">
            <route id="categoryheader" frontName="categoryheader">
                <module name="Sportys_Categoryheader" />
            </route>
        </router>
    </config>