diff --git a/pkg/azuread/datasource.go b/pkg/azuread/datasource.go
index 4e44792..f39bb80 100644
--- a/pkg/azuread/datasource.go
+++ b/pkg/azuread/datasource.go
@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log/slog"
 	"net/http"
 	"net/url"
 	"regexp"
@@ -238,6 +239,24 @@ func (d *Datasource) GetPage(ctx context.Context, request *Request) (*Response,
 	}
 
 	if res.StatusCode != http.StatusOK {
+		// TEMP: Log the response body for debugging purposes.
+		body, readErr := io.ReadAll(res.Body)
+		if readErr != nil {
+			slog.Error(
+				"Failed to read error response body",
+				slog.String("endpoint", endpoint),
+				"error", readErr,
+			)
+		} else {
+			slog.Error(
+				"Azure AD API error",
+				slog.Int("status", res.StatusCode),
+				slog.String("endpoint", endpoint),
+				slog.String("response", string(body)),
+			)
+		}
+		// END TEMP.
+
 		return response, nil
 	}
 
@@ -385,7 +404,8 @@ func IsAdvancedQuery(request *Request, endpoint string) bool {
 		}
 
 		// Check for 'ne' and 'not' operators using word boundary regex on decoded endpoint.
-		if neOperatorRegex.MatchString(decodedEndpoint) || notOperatorRegex.MatchString(decodedEndpoint) {
+		decodedEndpointLower := strings.ToLower(decodedEndpoint)
+		if neOperatorRegex.MatchString(decodedEndpointLower) || notOperatorRegex.MatchString(decodedEndpointLower) {
 			return true
 		}
 	}
diff --git a/pkg/azuread/datasource_test.go b/pkg/azuread/datasource_test.go
index 8957e7c..d02d298 100644
--- a/pkg/azuread/datasource_test.go
+++ b/pkg/azuread/datasource_test.go
@@ -1536,6 +1536,11 @@ func TestIsAdvancedQuery(t *testing.T) {
 			endpoint: "https://graph.microsoft.com/v1.0/users?$filter=displayName eq 'cannot'&$select=id",
 			want:     false,
 		},
+		"filter_odata_not": {
+			request:  &azuread.Request{},
+			endpoint: "https://graph.microsoft.com/v1.0/groups?$select=id&$top=1&$filter=NOT+groupTypes%2Fany%28c%3Ac+eq+%27DynamicMembership%27%29",
+			want:     true,
+		},
 
 		// Note: Advanced queries don't currently support $expand.
 		// This test documents that $expand alone does NOT trigger advanced query requirements.