Customer is not receiving the email notification

So we have a form for one of our customer, he emailed us and indicate that he is not receiving any email notification after user finished the form online.

I already used my personal account to test if it was the problem of the form setting, but it appears work fine with mine and other email addresses.

So could you help me to do a trace route to their email address? It is "neofc@sbcglobal.net"

Thank you!

Result: neofc@sbcglobal.net is IN the bounce list

Reason(s) : smtp; 553 5.3.0 flpd573 DNSBL:ATTRBL 521< 209.126.123.105

I have removed that email from the bounce list. Can you please tell him to try it again and tell us the result.