Problems sending email via Smarty

I joined Smarty on June 2nd, very recently

I have had a couple of domains for years, one main one for important stuff, banking, bills, etc and another one for newsletters etc

I use both "Fastmail" and "Runbox" to host the email for my domains, and have not experienced any problems with receiving and sending emails since I joined Smarty 

Suggest you have a look at your email hosts FAQ, as there may be / should be different ports you can use to send mail, whether you are using the old POP3 protocol or the newer IMAP Protocol. 

EDIT : Unless you are using Smarty email servers, which I dont think they provide to customers, then the issue you are currently experiencing is highly unlikely to be connected to / the fault of Smarty.

Which company is your email host ?