to set [ SPF ] DNS record
at [ cPanel-x3 theme ] ( not x10hosting Basic) home page --> [ Email Authentication ] --> look for [ SPF ]
be sure to click on [ Update ] after you enter your infomation
NOTE: external [ SMTP ] is blocked on x10hosting's free-hosting servers - all Email must go out through outbound spam filters on 10hosting's SMTP server - to be scanned for spam and phishing and other test