diff --git a/packages/backend/test-federation/test/utils.ts b/packages/backend/test-federation/test/utils.ts
index 2779eb7e81..9e82b12cbd 100644
--- a/packages/backend/test-federation/test/utils.ts
+++ b/packages/backend/test-federation/test/utils.ts
@@ -196,7 +196,11 @@ export async function uploadFile(
 	body.append('name', filename);
 
 	return await fetch(`https://${host}/api/drive/files/create`, { method: 'POST', body })
-		.then(async res => await res.json());
+		.then(async res => await res.json())
+		.catch(err => {
+			console.error('-- error :', JSON.stringify(err));
+			throw err;
+		});
 }
 
 export async function addCustomEmoji(
diff --git a/packages/misskey-js/src/api.ts b/packages/misskey-js/src/api.ts
index e663d712a7..57150875df 100644
--- a/packages/misskey-js/src/api.ts
+++ b/packages/misskey-js/src/api.ts
@@ -122,7 +122,10 @@ export class APIClient {
 						...body.error,
 					});
 				}
-			}).catch(reject);
+			}).catch(err => {
+				console.error('-- error :', JSON.stringify(err));
+				reject(err);
+			});
 		});
 	}
 }