[Plugin: Cimy Swift SMTP] Connection could not be established with host smtp.gmail.com [Connection t

Tried using STARTTLS?

Hi Marco – Well, this may be helpful to others:
After much investigation I found that my Firewall was blocking the IP’s. I use ConfigServer Security & Firewall.. lfd was seeing this as unauthorized. All i had to do was whitelist the SMTP IP’s and all is well.

This was covered already in the FAQ
https://www.marcocimmino.net/cimy-wordpress-plugins/cimy-swift-smtp/faq-and-comments/