Im trying to file my son tax return. i already did my daugter's tax return a few minutes ago. Why i cant g to the same profile to file my son's?

[be10091939]

why I cant use the same profile I set up to do my daughter's return

[sceptre2017]

Each online account can file only one return.  To attempt to file another return in the same account would essentially override the previous return.  You will need to create a new account to file your daughter's return.