Following a PHP upgrade to 7.2 it broke my Roundcube software. I ascertained that Roundcube 1.3.9. was PHP7.2 compatible and so went ahead and upgraded it. Since the upgrade I, along with what appears to many others, are having problems establishing an SMTP connection for outgoing mails (incoming mails are fine). The error I am receiving is a rather meaningless "SMTP Error (-1): Connection to server failed". Following suggestions by Googling the problem I have tried all combinations of ports and ssl/tls configurations but without success. It is worth pointing out that I am able to access my email through an Outlook 2017 client. My email server is a postfix/dovecot combination. I would be greatful to hear from anyone who has experienced my problem and managed to find a solution.