Magento extension install problem

Question

I installed amasty elasticsearch module. But I am getting errors like this. I researched a little. In the system.xml file it says make changes but I could not.

1 exception(s):

Exception #0 (Exception): Notice: Undefined index: id in /home/petyol/public_html/vendor/magento/module-config/Model/Config/Structure/Element/Iterator.php on line 72

Exception #0 (Exception): Notice: Undefined index: id in /home/petyol/public_html/vendor/magento/module-config/Model/Config/Structure/Element/Iterator.php on line 72

#1 Magento\Config\Model\Config\Structure\Element\Iterator->setElements() called at [vendor/magento/module-config/Model/Config/Structure.php:146]
#2 Magento\Config\Model\Config\Structure->getTabs() called at [generated/code/Magento/Config/Model/Config/Structure/Interceptor.php:23]
#3 Magento\Config\Model\Config\Structure\Interceptor->getTabs() called at [vendor/magento/module-config/Model/Config/Structure.php:209]
#4 Magento\Config\Model\Config\Structure->getFirstSection() called at [generated/code/Magento/Config/Model/Config/Structure/Interceptor.php:59]
#5 Magento\Config\Model\Config\Structure\Interceptor->getFirstSection() called at [vendor/magento/module-config/Controller/Adminhtml/System/AbstractConfig.php:63]
#6 Magento\Config\Controller\Adminhtml\System\AbstractConfig->dispatch() called at [vendor/magento/framework/Interception/Interceptor.php:58]
#7 Magento\Config\Controller\Adminhtml\System\Config\Index\Interceptor->___callParent() called at [vendor/magento/framework/Interception/Interceptor.php:138]
#8 Magento\Config\Controller\Adminhtml\System\Config\Index\Interceptor->Magento\Framework\Interception\{closure}() called at [vendor/magento/module-backend/App/Action/Plugin/Authentication.php:143]
#9 Magento\Backend\App\Action\Plugin\Authentication->aroundDispatch() called at [vendor/magento/framework/Interception/Interceptor.php:135]
#10 Magento\Config\Controller\Adminhtml\System\Config\Index\Interceptor->Magento\Framework\Interception\{closure}() called at [vendor/magento/framework/Interception/Interceptor.php:153]
#11 Magento\Config\Controller\Adminhtml\System\Config\Index\Interceptor->___callPlugins() called at [generated/code/Magento/Config/Controller/Adminhtml/System/Config/Index/Interceptor.php:32]
#12 Magento\Config\Controller\Adminhtml\System\Config\Index\Interceptor->dispatch() called at [vendor/magento/framework/App/FrontController.php:186]
#13 Magento\Framework\App\FrontController->processRequest() called at [vendor/magento/framework/App/FrontController.php:118]
#14 Magento\Framework\App\FrontController->dispatch() called at [vendor/magento/framework/Interception/Interceptor.php:58]
#15 Magento\Framework\App\FrontController\Interceptor->___callParent() called at [vendor/magento/framework/Interception/Interceptor.php:138]
#16 Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}() called at [vendor/magento/framework/Interception/Interceptor.php:153]
#17 Magento\Framework\App\FrontController\Interceptor->___callPlugins() called at [generated/code/Magento/Framework/App/FrontController/Interceptor.php:23]
#18 Magento\Framework\App\FrontController\Interceptor->dispatch() called at [vendor/magento/framework/App/Http.php:116]
#19 Magento\Framework\App\Http->launch() called at [generated/code/Magento/Framework/App/Http/Interceptor.php:23]
#20 Magento\Framework\App\Http\Interceptor->launch() called at [vendor/magento/framework/App/Bootstrap.php:263]
#21 Magento\Framework\App\Bootstrap->run() called at [pub/index.php:29]

system.xml

    <?xml version="1.0"?>
<!--
/**
 * @author Amasty Team
 * @copyright Copyright (c) 2018 Amasty (https://www.amasty.com)
 * @package Amasty_ElasticSearch
 */
-->

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Config:etc/system_file.xsd">
    <system>
        <section id="amasty_elastic" translate="label" type="text" sortOrder="51219" showInDefault="1" showInWebsite="0" showInStore="0">
            <resource>Amasty_ElasticSearch::config</resource>
            <class>separator-top</class>
            <label>Elastic Search</label>
            <tab>amasty</tab>
            <group id="amasty_information" translate="label" type="text" sortOrder="1" showInDefault="1" showInWebsite="1"
                   showInStore="1">
                <label>Information</label>
                <frontend_model>Amasty\ElasticSearch\Block\Adminhtml\System\Config\Information</frontend_model>
            </group>
            <group id="connection" translate="label" type="select" sortOrder="10" showInDefault="1" showInWebsite="0" showInStore="0">
                <label>Connection</label>
                <field id="engine" translate="label" type="select" sortOrder="10" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Search Engine</label>
                    <source_model>Magento\Search\Model\Adminhtml\System\Config\Source\Engine</source_model>
                </field>
                <field id="server_hostname" translate="label" type="text" sortOrder="20" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Elasticsearch Server Hostname</label>
                    <depends>
                        <field id="engine">amasty_elastic</field>
                    </depends>
                </field>
                <field id="server_port" translate="label" type="text" sortOrder="30" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Elasticsearch Server Port</label>
                    <validate>validate-greater-than-zero</validate>
                    <depends>
                        <field id="engine">amasty_elastic</field>
                    </depends>
                </field>
                <field id="index_prefix" translate="label" type="text" sortOrder="63" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Elasticsearch Index Prefix</label>
                    <depends>
                        <field id="engine">amasty_elastic</field>
                    </depends>
                </field>
                <field id="enable_auth" translate="label" type="select" sortOrder="64" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Enable Elasticsearch HTTP Auth</label>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                    <depends>
                        <field id="engine">amasty_elastic</field>
                    </depends>
                </field>
                <field id="username" translate="label" type="text" sortOrder="65" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Elasticsearch HTTP Username</label>
                    <depends>
                        <field id="enable_auth">1</field>
                    </depends>
                </field>
                <field id="password" translate="label" type="password" sortOrder="66" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Elasticsearch HTTP Password</label>
                    <depends>
                        <field id="enable_auth">1</field>
                    </depends>
                </field>
                <field id="server_timeout" translate="label" type="text" sortOrder="67" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Elasticsearch Server Timeout</label>
                    <validate>validate-greater-than-zero</validate>
                    <depends>
                        <field id="engine">amasty_elastic</field>
                    </depends>
                </field>
                <field id="test_connect" translate="button_label" sortOrder="68" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label/>
                    <button_label>Test Connection</button_label>
                    <frontend_model>Amasty\ElasticSearch\Block\Adminhtml\System\Config\ConnectionChecker</frontend_model>
                    <depends>
                        <field id="engine">amasty_elastic</field>
                    </depends>
                </field>
            </group>
            <group id="catalog" translate="label" type="select" sortOrder="20" showInDefault="1" showInWebsite="0" showInStore="0" >
                <label>Catalog</label>
                <field id="wildcard_mode" translate="label,comment" type="select" sortOrder="10" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Wildcard Type</label>
                    <comment>Specify the type of the autocomplete suggestion - the part of a word which will be auto-completed. Shoppers can input a half-finished word and get a relevant result.</comment>
                    <source_model>Amasty\ElasticSearch\Model\Source\WildcardMode</source_model>
                </field>
                <field id="wildcard_symbols" translate="label,comment" type="text" sortOrder="20" showInDefault="1" showInWebsite="0" showInStore="0" canRestore="1">
                    <label>Enable Wildcard After</label>
                    <validate>validate-greater-than-zero</validate>
                    <comment>Specify a number of symbols to apply autocomplete suggestion after.</comment>
                </field>
                <field id="spellcorrection_symbols" translate="label,comment" type="text" sortOrder="30" showInDefault="1" showInWebsite="0" showInStore="0" canRestore="1">
                    <label>Enable Spell Correction After</label>
                    <validate>validate-greater-than-zero</validate>
                    <comment>Specify a number of symbols to apply spell correction after.</comment>
                </field>
                <field id="max_items" translate="label" type="text" sortOrder="998" showInDefault="1" showInWebsite="0" showInStore="0" canRestore="1">
                    <label>Max Number of Search Results</label>
                    <comment>Specify the maximum number of items in the search results. Set 0 to use default Magento limitation (10000 items).</comment>
                    <validate>validate-zero-or-greater</validate>
                </field>
                <field id="long_tail" translate="label" type="select" sortOrder="1000" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Allow Special Characters</label>
                    <comment>Useful when customer uses a highly specific search phrase and words that contain slashes, hyphens, dashes or any other non-alphabetic symbols.</comment>
                    <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                    <backend_model>Amasty\ElasticSearch\Model\Adminhtml\System\Config\Backend\LongTail</backend_model>
                </field>
                <field id="query_settings" translate="label,comment" sortOrder="1010" showInDefault="1" showInWebsite="0" showInStore="0">
                    <label>Search Query Settings</label>
                    <frontend_model>Amasty\ElasticSearch\Block\Adminhtml\Form\Field\QuerySettings</frontend_model>
                    <backend_model>Amasty\ElasticSearch\Model\Config\QuerySettings</backend_model>
                    <comment><![CDATA[Specify the search type preferences for each product attribute. Please consult the <a href="https://amasty.com/docs/doku.php?id=magento_2:elastic_search#advanced_query_settings">user guide</a>.]]></comment>
                </field>
            </group>
        </section>
    </system>
</config>

Answer 1

Did you installed the amasty_elastic as a package in app/code.I was also faced similar kind of issue. Installing amasty_elasticsearch with composer solved the issue for me.