Woocommerce – Client does not get email on order completion

Hello all!

I am selling an excel file on my site.
The purchase is being completed automatically.
Then, I get an order email. my paypal registered email gets a message as well, but the client does not get a message with a link to the file! To be precise, he doesn’t get any mail!

I thought I should register an smtp provider for that, so I registers on mailgun.
But nothing changed.

Can you advise please?

Thank you.