Error after installing extension , Unable to access configuration in store, Mageplaza Extension [duplicate]

Question

Notice: Undefined index: id in /home/208806.cloudwaysapps.com/mnaanucsmd/public_html/vendor/magento/module-config/Model/Config/Structure/Element/Iterator.php on line 63

Error log record number: 1370744923540.

Got this error after trying to install a new module/extension mageplaza SMTP extension.

My iterator.php

public function setElements(array $elements, $scope)
    {
        $this->_elements = $elements;
        $this->_scope = $scope;
        if (count($elements)) {
            $lastElement = end($elements);
            $this->_lastId = $lastElement['id']; //<--- Line 63 is here
        }
    }

Answer 1

Check that Mageplaza_Core module installed and enabled:

From the Magento root directory type:

php bin/magento module:status Mageplaza_Core

You should see something like:

Module is enabled

In case you seeing something other you should install it (type from the Magento root directory):

composer require mageplaza/module-core

then enable it:

php bin/magento module:enable Mageplaza_Core

Note: On my server it looks like this:

and make update:

php bin/magento setup:upgrade
php bin/magento setup:di:compile

update static files if needed:

php bin/magento setup:static-content:deploy

After that it should work as expected.

Note: do not forget to run all commands from the correspondent web-server's user to avoid permissions issue.