The following error message is added to dblog because Solr 4.5.1 does not support the terms query parser. Later versions like Solr 6.6 or more recent support this query parser type.
Drupal\search_api_solr\SearchApiSolrException: Solr endpoint http://solr:8983/ bad request (code: 400, body: Unknown query parser 'terms', message: Solr HTTP error: OK (400) {"responseHeader":{"status":400,"QTime":2},"error":{"msg":"Unknown query parser 'terms'","code":400}} ). in Drupal\search_api_solr\SolrConnector\SolrConnectorPluginBase->handleHttpException() (line 1089 of C:\xampp\htdocs\cia-drupal\docroot\modules\contrib\search_api_solr\src\SolrConnector\SolrConnectorPluginBase.php)
Based on https://www.drupal.org/project/search_api_solr → , Solr 4.5.1 which is EOL but is still on the support matrix for search_api_solr. After looking into this, perhaps at least a wont-fix issue would be useful. Other than the above error, the 4.5.1 support is seems to work just fine.
Active
4.3
Solr Legacy
Did you enable the search_api_solr_legacy module?
And did you configure the Solr version to 4.x?
@mkalkbrenner Thank you for responding.
search_api_solr_legacy: Enabled @ 4.3.0
Connector Workarounds > Solr version override: Determine automatically