I’m running OpenHAB2.5.3 on a Mac, using the Mail binding to send email notifications to Gmail. Sending of emails intermittently fails with the subject error, whilst on other occassions the messages are delivered. When it fails these two lines appear in the log:
2022-03-24 11:20:33.529 [WARN ] [ab.binding.mail.internal.SMTPHandler] - Sending the email to the following server failed : smtp.gmail.com:465
2022-03-24 11:20:33.529 [WARN ] [ab.binding.mail.internal.SMTPHandler] - javax.mail.MessagingException: [EOF]
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting. Do not change this entry.
##
127.0.0.1 localhost
255.255.255.255 broadcasthost
::1 localhost
fe80::1%lo0 localhost