Getting issue while generating pdf wkhtmltopdf 0.12.6 (with patched qt) with pdfkit==0.6.1

Question

While generating pdf document from html string I am getting below error using Flask pdfkit(0.6.1) and wkhtmltopdf 0.12.6 (with patched qt). My application hosted on Ubuntu 18.04.5 LTS.

error : wkhtmltopdf reported an error: Loading pages (1/6) Error: Failed to load http://1/, with network status code 4 and http status code 0 - Socket operation timed out Error: Failed loading page http://1 (sometimes it will work just to ignore this error with --load-error-handling ignore) Exit with code 1 due to network error: TimeoutError

I have checked my html string but there are no existance of http://1/.

Below is my code

conf = pdfkit.configuration(wkhtmltopdf='/usr/local/bin/wkhtmltopdf')
pdfkit.from_string(html, PdfFilePath, options=options)