This might also be based on the page you are trying to render as PDF.
When you get this error:
Could not find file 'C:\Windows\TEMP\TEMPTCFTTNENMT00000000000000000000000000000000.pdf'.
Exit with code 1 due to network error: RemoteHostClosedError
you need to do what J. has recommended Above this will give you more insight indeed.
if you get something like this (ignore the SSL errors in dev and test there is no SSL certificate loaded at this time):
--------
C:\Program Files\OutSystems\Platform Server\running\HtmlToPdfConverter.356583579
\binaries>wkhtmltopdf https://<website>/xxxx/xxxxx.aspx Test.pdf
Loading pages (1/6)
Warning: SSL error ignored
Warning: SSL error ignored
Warning: SSL error ignored
Warning: SSL error ignored
Warning: SSL error ignored
Warning: SSL error ignored
Error: Failed to load https://<website>/XXXXXXX/undefined, with network status
code 203 and http status code 404 - Error downloading https://<website>/XXXX/undefined - server replied: Not Found
Counting pages (2/6)
Resolving links (4/6)
Loading headers and footers (5/6)
Printing pages (6/6)
Done
Exit with code 1 due to network error: ContentNotFoundError
--------
What above is stating is that the htmltopdf converter cannot access the page, one thing you need to remember is that the wkhtmltopdf.exe will be accessing the page / URL you have provided, so if the page is not set to anonymous it will not be able to access the page to render it as pdf.