register in subsite redirects me to main site

Hi

I have a testing site with multisite and i have installed and network activated appointment+ and when i try to register in order to get an appointment, that’s what happens.

i am in site.com/one/make-an-appointment/ and i try to register in the default link that comes with app+. And when i click the link it take me to site.com/wp-signup.php.

And in this case i become a client of the network and i just want to be user or client of “one”.

How can avoid that?

Thanks very much