I have android app (Flutter) and backend (NodeJs) I am using JWT authentication method there is no sign up , I previously added users to DB so they can logged in with their personal id and combination of their personal id and another personal number The problem is: when some users try to login to the application they successfully logged in but they found a profile for another user.
How can I troubleshot this problem?
In fact I didn`t try anything it is a strange problem for me