Class Magento\Elasticsearch\Model\Adapter\FieldMapperInterface does not exist
About the issue, our developer has checked and found the root of it is that the class Elasticsearch is not in Magento 2.2.x Community version; it is only in the Enterprise version.
Hence, to fix the issue, we would suggest that you should try to comment the code in the file etc/di.xml
<!-- Compatible with elasticsearch v2.4 && M2.1.8 --> <type name="Magento\Elasticsearch\SearchAdapter\Filter\Builder\Term"> <plugin name="bss-ln-convert-condition" type="Bss\LayerNavigation\Plugin\TermFilterBuilder" sortOrder="1" /> </type>
and then remove this file
Please check and follow our guide to fix the issue.
If you need any further support, please feel free to contact us at email@example.com
We'll be happy to support you.