diff --git a/sources/lib/Converter/PgJson.php b/sources/lib/Converter/PgJson.php
index <HASH>..<HASH> 100644
--- a/sources/lib/Converter/PgJson.php
+++ b/sources/lib/Converter/PgJson.php
@@ -117,9 +117,9 @@ class PgJson implements ConverterInterface
         if ($return === false) {
             throw new ConverterException(
                 sprintf(
-                    "Could not convert data to JSON. Driver returned '%s'.\n======\n%s\n",
-                    json_last_error(),
-                    $data
+                    "Could not convert %s data to JSON. Driver returned '%s'.",
+                    gettype($data),
+                    json_last_error()
                 )
             );
         }
fix error in PgJson exception if data not a string

When the data given to the converter is not a string (can be any
instances of classes implementing the `JsonSerializable` interface), and
the json_encode fails, the error message was formatted assuming it could
turn data into a string which may not be the case. This was creating a
fatal error in PHP.