Filing for my son for the first time

We are filing for my 16 y/o son for the first time, he doesn't have an online CRA account yet.  We have completed everything but when we go to net file, it rejects it saying either it isn't his first time filing (it is) or we haven't selected that it is his first time filing in the software (we did).  Not sure what else could be kicking that rejection.  Was hoping someone might be able to help.