Error when sending email with atachment

Traceback (innermost last):
  File "/home/erp/frappe-bench/apps/frappe/frappe/tasks.py", line 227, in sendmail
    recipients=recipients, cc=cc)
  File "/home/erp/frappe-bench/apps/frappe/frappeTraceback (innermost last):

  File "/home/erp/frappe-bench/apps/frappe/frappe/tasks.py", line 227, in sendmail

    recipients=recipients, cc=cc)

  File "/home/erp/frappe-bench/apps/frappe/frappe/core/doctype/communication/communication.py", line 118, in _notify

    self.prepare_to_notify(print_html, print_format, attachments)

  File "/home/erp/frappe-bench/apps/frappe/frappe/core/doctype/communication/communication.py", line 181, in prepare_to_notify

    /core/doctype/communication/communication.py", line 118, in _notify
    self.prepare_to_notify(print_html, print_format, attachments)
  File "/home/erp/frappe-bench/apps/frappe/frappe/core/doctype/communication/communication.py", line 181, in prepare_to_notify
    print_format=print_format, html=print_html))
  File "/home/erp/frappe-bench/apps/frappe/frappe/__init__.py", line 1037, in attach_print
    "fcontent": get_print(doctype, name, print_format=print_format, style=style, html=html, as_pdf=True)
  File "/home/erp/frappe-bench/apps/frappe/frappe/__init__.py", line 1020, in get_print
    return get_pdf(html)
  File "/home/erp/frappe-bench/apps/frappe/frappe/utils/pdf.py", line 16, in get_pdf
    pdfkit.from_string(html, fname, options=options or {})
  File "/home/erp/frappe-bench/env/src/pdfkit/pdfkit/api.py", line 68, in from_string
    return r.to_pdf(output_path)
  File "/home/erp/frappe-bench/env/src/pdfkit/pdfkit/pdfkit.py", line 140, in to_pdf
    raise IOError('wkhtmltopdf reported an error:\n' + stderr.decode('utf-8'))
 IOError: wkhtmltopdf reported an error:
Exit with code 1 due to network error: HostNotFoundError

Can you double check sender and recipient email address. Looks like due to incorrect email ID (error :HostNotFoundError)

@sanjay.kumar Its not due to email id,
When We send email without attachment then it sends.

The error is only coming when we send email with attachment.