Please note that SMTP is just an external protocol, Chevereto only connects to it and the system needs everything working properly (openssl, ports, etc) working in the target SMTP host. In your case I'm seeing a timeout, for which you should check if your webserver is capable to reach that server and if the port that you want to use is enabled for this connection.
You should try with a different SMTP server/port and if you want to me to test the whole thing I also need the alleged SMTP credentials. Do please assume that I need everything to work with, I think that you realize that the less you give me to work with the more useless my answers gets.
If you want a true reliable solution go for outsourced SMTP (like sendgrid) because in house solutions are always horrible for the email delivery business.
This is exactly a good example of how Chevereto tech support is misunderstood.
The fact that Chevereto interacts with SMTP doesn't mean that we have to provide you support in how the SMPT connection is working in your server. It is another thing, not handled by Chevereto and not dependant on Chevereto.
You have plenty tools to debug SMTP, in fact, soon as you enable debug_level 3 you will see everything that your server throws (if any). Keep in mind that Chevereto only outputs whatever your SMTP server throws. If your SMTP doesn't throw anything it is impossible to detect the problem in that layer and you will have to dig in the SMTP server logs.
Please realize that the scope of this support is Chevereto and nothing else. In the past, I've helped a lot of users and clients regarding server issues and I won't do it anymore because it just eats my time and goodwill.