title: can't use sjPlot in R
body: <p>I followed the instructions on <a href="https://strengejacke.github.io/sjPlot/" rel="noreferrer">https://strengejacke.github.io/sjPlot/</a> to install the package but despite downloading and installing all the packages, I can't use them because I keep getting the error message
  <code>could not find function "sjP.lmer"</code></p>
  
  <p>does anyone know where this is coming from? I'd be happy to provide more details but I don't even know where to look for them...</p>