Email Not sending to Yahoo mail from go daddy website


New Email

I have a website called, which is hosted by Go Daddy. My client has an email account with Yahoo.

They need a PDF attached to the orders, their customers make in the store powered by WooCommerce. I'm using a plugin called 'WooCommerce PDF Invoices & Packing Slips'.

When I do a test order, it goes to my email account (btinternet) absolutely fine but it doesn't even go to the spam folder on the yahoo account.

I think their may be some firewall blocking either from Yahoo end, Go daddy or both.

Can someone please help whether I can get this working!