Resolving issues with order confirmation email reception

Client:
Is it "normal" not to receive the order confirmation email?

Technical Advisor:
Hello, no. I will check that for you.

Technical Advisor:
We have received your order. The confirmation email may be in your spam folder.

Technical Advisor:
I will resend it to you tomorrow morning.

Client:
I found it in the spam folder, which is surprising since it's my first contact with you! Thank you very much.

Technical Advisor:
Have a nice day...