Error(s) in re-building vignettes:
--- re-building ‘ggeffects.Rmd’ using rmarkdown
Standard errors are on link-scale (untransformed).
--- finished re-building ‘ggeffects.Rmd’

--- re-building ‘introduction_effectsatvalues.Rmd’ using rmarkdown
Model has log-transformed predictors. Consider using `terms="hp [exp]"` to back-transform scale.
Model has log-transformed predictors. Consider using `terms="hp [exp]"` to back-transform scale.
Model has log-transformed predictors. Consider using `terms="hp [exp]"` to back-transform scale.
Model has log-transformed predictors. Consider using `terms="hp [exp]"` to back-transform scale.
Learn more about sjmisc with 'browseVignettes("sjmisc")'.
Loading required package: Matrix
boundary (singular) fit: see ?isSingular
Model contains polynomial or cubic / quadratic terms. Consider using `terms="c12hour [all]"` to get smooth plots. See also package-vignette 'Marginal Effects at Specific Values'.
Model contains polynomial or cubic / quadratic terms. Consider using `terms="c12hour [all]"` to get smooth plots. See also package-vignette 'Marginal Effects at Specific Values'.
Model contains polynomial or cubic / quadratic terms. Consider using `terms="c12hour [all]"` to get smooth plots. See also package-vignette 'Marginal Effects at Specific Values'.
--- finished re-building ‘introduction_effectsatvalues.Rmd’

--- re-building ‘introduction_plotcustomize.Rmd’ using rmarkdown
Scale for 'x' is already present. Adding another scale for 'x', which will replace the existing scale.
Scale for 'colour' is already present. Adding another scale for 'colour', which will replace the existing scale.
--- finished re-building ‘introduction_plotcustomize.Rmd’

--- re-building ‘introduction_plotmethod.Rmd’ using rmarkdown
Loading required namespace: ggplot2
Loading required namespace: lme4
--- finished re-building ‘introduction_plotmethod.Rmd’

--- re-building ‘introduction_randomeffects.Rmd’ using rmarkdown
Loading required package: Matrix
Loading required namespace: ggplot2
Quitting from lines 71-79 (introduction_randomeffects.Rmd) 
Error: processing vignette 'introduction_randomeffects.Rmd' failed with diagnostics:
object 'site' not found
--- failed re-building ‘introduction_randomeffects.Rmd’

--- re-building ‘practical_logisticmixedmodel.Rmd’ using rmarkdown
Loading required package: Matrix
Loading required namespace: ggplot2
Data were 'prettified'. Consider using `terms="var_cont [all]"` to get smooth plots.
Warning in checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
  unable to evaluate scaled gradient
Warning in checkConv(attr(opt, "derivs"), opt$par, ctrl = control$checkConv,  :
   Hessian is numerically singular: parameters are not uniquely determined
--- finished re-building ‘practical_logisticmixedmodel.Rmd’

--- re-building ‘technical_differencepredictemmeans.Rmd’ using rmarkdown
Loading required namespace: emmeans
Loading required namespace: ggplot2
--- finished re-building ‘technical_differencepredictemmeans.Rmd’

--- re-building ‘technical_stata.Rmd’ using rmarkdown
Data were 'prettified'. Consider using `terms="var2 [all]"` to get smooth plots.
Loading required namespace: ggplot2
--- finished re-building ‘technical_stata.Rmd’

SUMMARY: processing the following file failed:
  ‘introduction_randomeffects.Rmd’

Error: Vignette re-building failed.
Execution halted