From the forums it looks like this is a fairly common problem but I've never come across how it actually gets resolved?
I have contacted Zoho who have told me that nothing appears to be wrong with my account and to get in touch with the email providers I am trying to contact (BT internet etc). However, I obviously can't contact every potential email provider. Could someone please look into this properly for me? It is holding up business. The account is
samantha@harrisblu.com .