Mail being returned

[Sanke]

Morning all
I have a customer (company) who I regularly email to. As of yesterday when I email them the email comes straight back returned by Symantec error 553. I email several different people all a the same company & I am getting the same result. if I email other people the email goes through no problem.I have contacted the company & he say they are having no problems Help please

 

[Goody]

Check this out -> Unable to send email to certain domains, I get a 553 SPF error message

Regards