Issue sending outgoing email

[tezenj]

I am currently using this software on OSX High SIerra and every time I attempt to attach a picture and then put in the server information and credentials that are correct for gmail, I get an error "connection failed: The remote host closed the connection" even though everything is correct. I also have 3rd party apps allowed in gmail. What am I missing here?

[xnview]

it's a known issue