Hello! We are a web design agency and looking for a tool to use as Wordpress SMTP connection for our clients. its nothing big or complicated, but since Microsoft discontinued their SMTP sendings we need a solution for lot of our clients. Can we purchase the Tier 4 plan and add/verify all our client domains there and use SMTP sending? No big marketing campaigns needed. Just SMTP for contact forms and signup forms. our clients do not need separate login. Thx