Create new tab config in admin magento2 error sorting?

Question

I had created new module in magento2, When I create new tab get error:

Exception #0 (Exception): Warning: Invalid argument supplied for foreach() in ...\vendor\magento\module-config\Model\Config\Structure\Mapper\Sorting.php on line 34

This code in system.xml file.

   <?xml version="1.0"?>
<!--
/**
 * @author Magento Addons Team
 * @copyright Copyright (c) 2015 Magento Addons (https://www.magentoaddons.com)
 * @package Custom_Base
 */ 
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <tab id="new_module" translate="label" sortOrder="100">
            <label>New module</label>
        </tab>
        <section id="base" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
            <label>Base Configuration</label>
            <tab>new_module</tab>
            <resource>Custom_Base::config_module</resource>
            <group id="general" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Base</label>
                <field id="enabled" translate="label" type="select" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Enable Base</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                </field>
            </group>
        </section>
    </system>
</config>

Many thanks!

Answer 1

There is extra space before <?xml version="1.0"?>. Otherwise your code works for me.

Try after removing space.

Below Code:

<?xml version="1.0"?>
    <!--
    /**
     * @author Magento Addons Team
     * @copyright Copyright (c) 2015 Magento Addons (https://www.magentoaddons.com)
     * @package Custom_Base
     */ 
    -->
    <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
        <system>
            <tab id="new_module" translate="label" sortOrder="100">
                <label>New module</label>
            </tab>
            <section id="base" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Base Configuration</label>
                <tab>new_module</tab>
                <resource>Custom_Base::config_module</resource>
                <group id="general" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                    <label>Base</label>
                    <field id="enabled" translate="label" type="select" sortOrder="10" showInDefault="1" showInWebsite="1" showInStore="1">
                        <label>Enable Base</label>
                        <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                    </field>
                </group>
            </section>
        </system>
    </config>

• Please Delete VAR/GENERATION directory
• Clear the cache and also remove cache folder from VAR directory
• Run cache:clean and cache:flush Command and then try