MY SMTP server on Plusnet will NOT support SSL/ TLS so eM client fails to SEND ANY MAIL -POP3 works ok

MY POP/ SMTP SERVER is hosted by PLUSNET & THEY DO NOT SUPPORT SMTP SSL / TLS.
Consequently I cannot set up ANY outgoing MAIL using eM Client on my MacBook Pro running latest MacOs High Sierra 10.13.6.
POP email download works perfectly but when I try to sen mail, eM jams up.
It also cannot down load SENT mail from server and is constantly busy for 10-20 mins and then fails

Usually the only time you see servers not supporting SSL/TLS is when you and the server are on the same network; like a company email server, or where your home Intenet provider is also your email provider. This is because not using SSL/TLS is unsecure. In fact servers usually refuse connections that are not using SSL/TLS when you are using another Internet provider, like if you try to use your MacBook with a coffee shop WiFi connection, or you try to connect from your friend’s house and they use another Internet provider. This is because if they allow unsecure connections from other networks, they are completely open for spammers to take advantage of their SMTP servers.

But anyway . . .

Go to Menu > Tools > Accounts and click on the SMTP tab for your account. Change the port to  25 and the security policy to  Use SSL/TLS if available.