Error while printing in pdf

Hi i got the pdf error while printing th quotation

File “/home/frappe/frappe-bench/apps/frappe/frappe/handler.py”, line 92, in execute_cmd
ret = frappe.call(method, **frappe.form_dict)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 751, in call
return fn(*args, **newargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/templates/pages/print.py”, line 115, in download_pdf
frappe.local.response.filecontent = get_pdf(html)
File “/home/frappe/frappe-bench/apps/frappe/frappe/utils/pdf.py”, line 30, in get_pdf
pdfkit.from_string(html, fname, options=options or {})
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pdfkit/api.py”, line 68, in from_string
return r.to_pdf(output_path)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pdfkit/pdfkit.py”, line 116, 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: ContentNotFoundError

You have a bad image link in your Print Format.

so, what i have to do now,

Please give me the proper suggestion, that i should face this problem again