When you created an account on the OBiTALK Web Portal, you chose a username and a password.
When logging into the OBi device itself, the default username/password is admin/admin. If you added the OBi device to the Dashboard of the OBiTALK Web Portal, the OBi device password may have been changed by the OBiTALK Web Portal. The current password should be display in the OBiTALK Web Portal.