I got similar errors, although not the same with LO 18.104.22.168 under Win7 :
I cannot set the SMTP server connexion. When testing the connexion, it takes ages (>10 mn) and in the end I have the following error message :
LibreOffice could not connect to the outgoing mail server. Check your system’s settings and the settings in LibreOffice. Check the server name, the port and the secure connections settings
<class ‘smtplib.SMTPServerDisconnected’>: Connection unexpectedly closed, traceback follows
C:\Program Files (x86)\LibreOffice 5\program\python-core-3.3.0\lib\smtplib.py:375 in function getreply() [raise SMTPServerDisconnected(“Connection unexpectedly closed”)]
C:\Program Files (x86)\LibreOffice 5\program\python-core-3.3.0\lib\smtplib.py:322 in function connect() [(code, msg) = self.getreply()]
C:\Program Files (x86)\LibreOffice 5\program\python-core-3.3.0\lib\smtplib.py:241 in function init() [(code, msg) = self.connect(host, port)]
C:\Program Files (x86)\LibreOffice 5\program\mailmerge.py:106 in function connect() [self.server = smtplib.SMTP(server, port,timeout=tout)]
I am pretty sure the parameters I use are correct since they come from my Thunderbird settings.
The only parameter I doubt is the SSL connexion, as I don’t know if that means it is SSL/TLS or STARTTLS, since I need to use different ports.
I also can’t set the connexion with LO 5.4.03 under Linux Mint 17.3 Cinnamon, although I don’t get an error message at all.