diff --git a/packages/backend/src/core/VideoProcessingService.ts b/packages/backend/src/core/VideoProcessingService.ts
index ffb757335..e157160b4 100644
--- a/packages/backend/src/core/VideoProcessingService.ts
+++ b/packages/backend/src/core/VideoProcessingService.ts
@@ -50,7 +50,14 @@ export class VideoProcessingService {
 
 	@bindThis
 	public getExternalVideoThumbnailUrl(url: string): string | null {
-		if (this.config.videoThumbnailGenerator == null) return null;
+		if (this.config.videoThumbnailGenerator == null) {
+			return appendQuery(
+				`${this.config.url}/proxy/thumbnail.webp`,
+				query({
+					url,
+				}),
+			);
+		}
 
 		return appendQuery(
 			`${this.config.videoThumbnailGenerator}/thumbnail.webp`,