files/search_v2 400 error

I'm new to Dropbox API.

I'm trying to use files/search_v2 API and got a 400 error with a bearer token created by My Apps in my developer console. I'm trying to access files in my Team's folders. I've tried the following:

1. When I use the access token generated by Dropbox API Explorer, that works.

2. When I use the same CURL command by replacing the bearer token generated by My Apps, it's not working and got the HTTP 400 error.

curl -X POST https://api.dropboxapi.com/2/files/search_v2 \
  --header "Authorization: Bearer $TOKEN" \
  --header 'Content-Type: application/json' \
  --data '{"query":"test"}'

3. When I use the same bearer token generated by My Apps with another Dropbox API, such as team/get_info, it works.

4. That makes me wonder if I need to include all the read scopes in my app. I tested with all the read scopes in both User and Teams scopes, but (2) still didn't work.

I'm trying to make (2) work with My App. Any clues/tips/guidance are greatly appreciated!