Flows are being serviced through a variety of accounts.
1. Flow’s own account. (Only for finding a password)
https://flow.appplay.co.kr/login.act
On the login page, select 'Forgot your password?'
2. For Bizplay account users.
If you forgot your ID or password, you can find it through the pages below.
Find ID
https://www.bizplay.co.kr/comm_0022_01.act
Find password
https://www.bizplay.co.kr/comm_0023_01.act
3. For Kakao Talk, Google account users.
Since Kakao Talk and Google accounts manage their accounts by themselves, you need to ask them.