DAT One Mobile allows only one user session at a time. If the username/email and password have been shared with another user, you will be logged out of the application upon them logging in.
Example: A user can sign into one session of DAT One Mobile. If one user tries to sign into both at the same time, the first user will be kicked out.
Note: You are allowed to log into both DAT One Web (one.dat.com) and DAT One Mobile or at the same time with a username/email and password.
If you would like a second user to be able to access DAT as the same time, you will need to purchase an additional user license from DAT.