Error(s) in re-building vignettes:
  ...
--- re-building ‘creating-vms.Rmd’ using rmarkdown
--- finished re-building ‘creating-vms.Rmd’

--- re-building ‘docker-ssh-futures.Rmd’ using rmarkdown
--- finished re-building ‘docker-ssh-futures.Rmd’

--- re-building ‘docker.Rmd’ using rmarkdown
--- finished re-building ‘docker.Rmd’

--- re-building ‘example-workflows.Rmd’ using rmarkdown
--- finished re-building ‘example-workflows.Rmd’

--- re-building ‘gpu.Rmd’ using rmarkdown
--- finished re-building ‘gpu.Rmd’

--- re-building ‘installation-and-authentication.Rmd’ using rmarkdown
--- finished re-building ‘installation-and-authentication.Rmd’

--- re-building ‘massive-parallel.Rmd’ using rmarkdown
Could not fetch https://user-images.githubusercontent.com/3155884/36549126-494a99ca-17f2-11e8-8338-f5769a629749.png
HttpExceptionRequest Request {
  host                 = "user-images.githubusercontent.com"
  port                 = 443
  secure               = True
  requestHeaders       = []
  path                 = "/3155884/36549126-494a99ca-17f2-11e8-8338-f5769a629749.png"
  queryString          = ""
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
  proxySecureMode      = ProxySecureWithConnect
}
 (InternalException (HandshakeFailed (Error_Protocol ("certificate has expired",True,CertificateExpired))))
Error: processing vignette ‘massive-parallel.Rmd’ failed with diagnostics:
pandoc document conversion failed with error 61
--- failed re-building ‘massive-parallel.Rmd’

--- re-building ‘opencpu-api-server.Rmd’ using rmarkdown
--- finished re-building ‘opencpu-api-server.Rmd’

--- re-building ‘persistent-rstudio.Rmd’ using rmarkdown
--- finished re-building ‘persistent-rstudio.Rmd’

--- re-building ‘rstudio-team.Rmd’ using rmarkdown
--- finished re-building ‘rstudio-team.Rmd’

--- re-building ‘scheduled-rscripts.Rmd’ using rmarkdown
--- finished re-building ‘scheduled-rscripts.Rmd’

--- re-building ‘shiny-app.Rmd’ using rmarkdown
--- finished re-building ‘shiny-app.Rmd’

--- re-building ‘single-scheduler.Rmd’ using rmarkdown
--- finished re-building ‘single-scheduler.Rmd’

--- re-building ‘troubleshooting.Rmd’ using rmarkdown
--- finished re-building ‘troubleshooting.Rmd’

SUMMARY: processing the following file failed:
  ‘massive-parallel.Rmd’

Error: Vignette re-building failed.
Execution halted