Using licence on 2 computers

[SaanichGAS]

I have installed the Desktop version (which I downloaded from TurboTax.ca) on one system. When my son downloads and installs on a 2nd system (I am licensed for 3 as stated above) using the same license code, he receives Error code 603. Something here is amiss. How do I get past this error?

[TurboTaxSusan]

@SaanichGAS Your son has to log into the same account that you used when you first used your licence code.