diff --git a/module/VuFind/src/VuFind/Recommend/ConsortialVuFind.php b/module/VuFind/src/VuFind/Recommend/ConsortialVuFind.php
index 8b8ccbe3a1e..c0e5638b594 100644
--- a/module/VuFind/src/VuFind/Recommend/ConsortialVuFind.php
+++ b/module/VuFind/src/VuFind/Recommend/ConsortialVuFind.php
@@ -33,6 +33,7 @@
 use VuFind\Connection\ExternalVuFind as Connection;
 
 use function intval;
+use function is_callable;
 
 /**
  * ConsortialVuFind Recommendations Module
@@ -111,9 +112,9 @@ class ConsortialVuFind implements RecommendInterface, \Laminas\Log\LoggerAwareIn
     /**
      * Query string from the original search results
      *
-     * @var string
+     * @var ?string
      */
-    protected $queryString;
+    protected $queryString = null;
 
     /**
      * Constructor
@@ -198,7 +199,10 @@ public function init($params, $request)
      */
     public function process($results)
     {
-        $this->queryString = $results->getParams()->getQuery()->getString();
+        $query = $results->getParams()->getQuery();
+        if (is_callable([$query, 'getString'])) {
+            $this->queryString = $query->getString();
+        }
     }
 
     /**
@@ -208,7 +212,7 @@ public function process($results)
      */
     public function getResults()
     {
-        if (!$this->hasMinimumConfig) {
+        if (!$this->hasMinimumConfig || !$this->queryString) {
             return [];
         }
 
diff --git a/module/VuFind/src/VuFind/Recommend/Databases.php b/module/VuFind/src/VuFind/Recommend/Databases.php
index 39de1e387f4..2bcfbb82a6e 100644
--- a/module/VuFind/src/VuFind/Recommend/Databases.php
+++ b/module/VuFind/src/VuFind/Recommend/Databases.php
@@ -33,6 +33,7 @@
 
 use function count;
 use function intval;
+use function is_callable;
 use function strlen;
 
 /**
@@ -272,7 +273,10 @@ public function getResults()
 
         // Add databases from search query
         if ($this->useQuery) {
-            $query = strtolower($this->results->getParams()->getQuery()->getString());
+            $queryObject = $this->results->getParams()->getQuery();
+            $query = is_callable([$queryObject, 'getString'])
+                ? strtolower($queryObject->getString())
+                : '';
             if (strlen($query) >= $this->useQueryMinLength) {
                 foreach ($nameToDatabase as $name => $databaseInfo) {
                     if (str_contains(strtolower($name), $query)) {