We are are small charity that sends out emails when people make donations or register for events. At the moment we have an event that people register for using an app that runs on our Plesk hosting domain. The apps send a confirmation email when people register giving information that is essential for people to receive. 50% of the time people do not receive this email. After many hours on the phone to GoDaddy support and getting a wide range of advice it seems that the reason it that the IPs of the GoDaddy SMTP servers are constantly getting black listed, we use 'relay-hosting.secureserver.net'. I was given a link to request the black list be removed but an hour later it happens again. I have been told that the SMTP servers we use are in Singapore and are shared and someone (not us) must be sending out spam. Problem is that there are a number of IPs that are used by GoDaddy and you can never be sure which one your email is going to be sent out by and which ones are black listed. What you can be sure of is that in a 24 period half the emails you send are going to be sent by a GoDaddy IP address that is black listed.
To cut a long story short it seems that whatever GoDaddy say they can't stop this from happening.
Has anyone used any 3rd party SMTP servers that do not get constantly black listed? Our only other alternative is to move off GoDaddy which we would prefer not to do.