diff --git a/src/api.ts b/src/api.ts
index e744483..e196a49 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -100,13 +100,13 @@ router.patch('/pool', (req, res) => {
 
 router.delete('/pool', (req, res) => {});
 
-router.get('/group', (req, res) => {
+router.get('/group', async (req, res) => {
 	if (typeof req.query.groupID != 'string') {
 		return res.json({ status: 'error' });
 	}
 
 	let groupID = req.query.groupID;
-	let group = getGroupByID(groupID);
+	let group = await getGroupByID(groupID);
 
 	if (group) {
 		res.json({ status: 'success', data: group });
@@ -117,6 +117,7 @@ router.get('/group', (req, res) => {
 
 router.get('/group_pools', async (req, res) => {
 	if (typeof req.query.groupID != 'string') {
+		res.json({ status: 'error', error: 'need_group_id' });
 		return;
 	}
 
diff --git a/src/data.ts b/src/data.ts
index 88f2aff..2596426 100644
--- a/src/data.ts
+++ b/src/data.ts
@@ -1,5 +1,6 @@
 import { IonProfile } from './auth_ion';
 import { GroupModel, PoolModel, UserModel } from './models';
+import { ObjectId } from 'mongodb';
 
 /**
  *
@@ -17,7 +18,7 @@ export function getGroupsWithUser(userID: string) {
  */
 export async function getPoolsWithUser(userID: string) {
 	return await PoolModel.find({
-		participant_ids: { $all: [userID] },
+		participant_ids: { $all: [new ObjectId(userID)] },
 	}).exec();
 }
 
@@ -25,16 +26,17 @@ export async function getUserByID(userID: string) {
 	if (userID == null) {
 		return undefined;
 	}
-	return (await UserModel.findById(userID).exec()).toJSON();
+	let doc = await UserModel.findById(new ObjectId(userID)).exec();
+	return doc?.toJSON();
 }
 
 export async function getPoolByID(poolID: string) {
-	let doc = await PoolModel.findById(poolID).exec();
+	let doc = await PoolModel.findById(new ObjectId(poolID)).exec();
 	return doc?.toJSON();
 }
 
 export async function getGroupByID(groupID: string) {
-	let doc = await GroupModel.findById(groupID).exec();
+	let doc = await GroupModel.findById(new ObjectId(groupID)).exec();
 	return doc?.toJSON();
 }