Error Log - frappe.email.queue.flush

I get this error from time to time. How do i resolve it?

[Errno -2] Name or service not known
Traceback (most recent call last):
  File "/home/administrator/frappe-bench/apps/frappe/frappe/email/queue.py", line 412, in send_one
    smtpserver.sess.sendmail(email.sender, recipient.recipient, encode(message))
  File "/home/administrator/frappe-bench/apps/frappe/frappe/email/smtp.py", line 208, in sess
    raise_(frappe.ValidationError, e, traceback)
  File "/home/administrator/frappe-bench/apps/frappe/frappe/email/smtp.py", line 181, in sess
    cint(self.port) or None)
  File "/usr/lib/python2.7/smtplib.py", line 256, in __init__
    (code, msg) = self.connect(host, port)
  File "/usr/lib/python2.7/smtplib.py", line 316, in connect
    self.sock = self._get_socket(host, port, self.timeout)
  File "/usr/lib/python2.7/smtplib.py", line 291, in _get_socket
    return socket.create_connection((host, port), timeout)
  File "/usr/lib/python2.7/socket.py", line 553, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
ValidationError: [Errno -2] Name or service not known

It looks like you are having some network or service timeout issues with email service provider, what provider are you using?

Using free Gmail account.

Regular email services like Gmail will restrict you to a limited number of emails per day.
so thats what might be causing the error

how many emails you are trying to send through your gmail? you should consider SMTP relay service like sendgrid or sparkpost

https://erpnext.org/docs/user/manual/en/setting-up/email/email-account.html