I have a friend from the uk and i cannot find her email addres anywhere? I have been searching so many sites for an email address finder but they all cost money! Does anyone know any sites that i can find my friends email thats free?

I need to send email to my friend but I don’t really remember the exact address he gave. I tried to send to the following address : gotardi_luca@hotmail.com I’m not sure if the address correct or not I try to send many many times but always failed. Is there any free email address finder I can use?
or can anybody help me what to do? thank you!