I’m working for a genuine company and we are into analysis, and usually send mass mailing, currently using a mass mail service provider from past two years, now the mass mail doesn’t deliver to our domain itself, when asked for the web mail server support they said that the firewall is blocking this particular mass mailing service providers because its black listed
Can you guys please let me know which mass mail service providers are best and can be trusted, not from google or somewhere heard, please suggest if you are really using it and which is not black listed anywhere in the firewalls.