Error(s) in re-building vignettes:
  ...
--- re-building 'data_mashups.Rmd' using rmarkdown
Quitting from lines 43-45 (data_mashups.Rmd) 
Error: processing vignette 'data_mashups.Rmd' failed with diagnostics:
HTTP failure: 503
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>503 Service Unavailable</title>
</head><body>
<h1>Service Unavailable</h1>
<p>The server is temporarily unable to service your
request due to maintenance downtime or capacity
problems. Please try again later.</p>
<hr>
<address>Apache/2.4.38 (Debian) Server at api.opentreeoflife.org Port 443</address>
</body></html>

--- failed re-building 'data_mashups.Rmd'

--- re-building 'meta-analysis.Rmd' using rmarkdown
Quitting from lines 107-109 (meta-analysis.Rmd) 
Error: processing vignette 'meta-analysis.Rmd' failed with diagnostics:
HTTP failure: 503
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>503 Service Unavailable</title>
</head><body>
<h1>Service Unavailable</h1>
<p>The server is temporarily unable to service your
request due to maintenance downtime or capacity
problems. Please try again later.</p>
<hr>
<address>Apache/2.4.38 (Debian) Server at api.opentreeoflife.org Port 443</address>
</body></html>

--- failed re-building 'meta-analysis.Rmd'

--- re-building 'rotl.Rmd' using rmarkdown
Quitting from lines 64-67 (rotl.Rmd) 
Error: processing vignette 'rotl.Rmd' failed with diagnostics:
HTTP failure: 503
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>503 Service Unavailable</title>
</head><body>
<h1>Service Unavailable</h1>
<p>The server is temporarily unable to service your
request due to maintenance downtime or capacity
problems. Please try again later.</p>
<hr>
<address>Apache/2.4.38 (Debian) Server at api.opentreeoflife.org Port 443</address>
</body></html>

--- failed re-building 'rotl.Rmd'

SUMMARY: processing the following files failed:
  'data_mashups.Rmd' 'meta-analysis.Rmd' 'rotl.Rmd'

Error: Vignette re-building failed.
Execution halted