The exit status code '1' says something went wrong:
stderr: "Loading pages (1/6)
[>                                                           ] 0%
[======>                                                     ] 10%
Warning: Blocked access to file                                   
Warning: Blocked access to file 
Warning: Blocked access to file 
Warning: Blocked access to file 
Warning: Blocked access to file 
Warning: Blocked access to file 
[========>                                                   ] 14%
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
[===============>                                            ] 25%
Warning: Blocked access to file                                   
Error: Failed to load about:blank, with network status code 301 and http status code 0 - Protocol "about" is unknown
[==================>                                         ] 30%
[====================>                                       ] 34%
[======================>                                     ] 38%
[========================>                                   ] 41%
[==========================>                                 ] 44%
[===========================>                                ] 46%
[============================>                               ] 48%
[============================================================] 100%
Counting pages (2/6)                                               
[============================================================] Object 1 of 1
Resolving links (4/6)                                                       
[============================================================] Object 1 of 1
Loading headers and footers (5/6)                                           
[=>                                                          ] 3%
[===>                                                        ] 6%
[======>                                                     ] 10%
[======>                                                     ] 10%
[=============>                                              ] 23%
[========================>                                   ] 40%
[===============================>                            ] 53%
[==========================================>                 ] 70%
[==========================================>                 ] 71%
[===========================================>                ] 72%
[===========================================>                ] 73%
[============================================================] 100%
Printing pages (6/6)                                               
[>                                                           ] Preparing
[===================>                                        ] Page 1 of 3
[=======================================>                    ] Page 2 of 3
[============================================================] Page 3 of 3
Done                                                                      
Exit with code 1 due to network error: ProtocolUnknownError
"
stdout: ""
command: /usr/local/bin/wkhtmltopdf --dpi '90' --image-dpi 300 --lowquality --margin-bottom '10' --margin-left '5' --margin-right '5' --margin-top '28' --enable-external-links --enable-internal-links --enable-javascript --javascript-delay '2000' --header-html '/data/sites/web/allure-recom/tmp/knp_snappy664af9794ebad9.23479280.html' --header-spacing '7' '/data/sites/web/allure-recom/tmp/knp_snappy664af9794e71a5.79753445.html' '/data/sites/web/allure-recom/tmp/knp_snappy664af9794eb8c8.86004064.pdf'.