Please provide information about why you are having these difficulties. Are you getting error messages?

yes error message Unable to establish a secure link with outgoing server (SMTP) using STARTTLS since it does not advertise that feature. Switch off STARTTLS for that server or contact your service provider

So, that would suggest that the authentication settings for the outgoing server (SMTP) are incorrect. If you search for your Email Provider's recommended settings, you should check these with those you have input (at Hamburger (top right)/Account Settings/Outgoing Server (SMTP) (left)). Alternatively, contact your Email Provider.