Magento2 Elastic Search Configuration Issue

Question

I am using following configurations for my magento2 project

Ubuntu 18.04
PHP 7.2
MYSQL 5.7
Elastic Search 7.x
Magento 2.3.5-p1

When i enabled elastic search in magento2 admin panel , the connection was successful but getting below error when i run indexer or navigates to category pages.

Fatal error: Uncaught Error: Cannot instantiate interface Magento\AdvancedSearch\Model\Client\ClientOptionsInterface in /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php:121 Stack trace: 
#0 /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/Compiled.php(108): Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject('Magento\\Advance...', Array) 
#1 /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Advance...') 
#2 /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectManager\Factory\Compiled->get('Magento\\Advance...') 
#3 /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/Compiled.php(150): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Elastic...') 
#4 /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/Compiled.php(79): Magento\Framework\ObjectMan in /var/www/html/myproj/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php on line 121

Any solution for this?

Answer 1

Check if the required modules are installed and enabled.

In my case (during an update from Magento 2.3 to Magento 2.4) the modules "Magento_Elasticsearch" and "Magento_Elasticsearch6" were disabled.

"Magento_Elasticsearch" contains the implementation of the "Magento\AdvancedSearch\Model\Client\ClientOptionsInterface".