title: auto_arima model.fit() giving errors
body: <p>So I use auto arima to fit my data and then fit that model and plot predict the results. However, when using the model that auto arima recc, I get the following errors at times</p>
  <ol>
  <li>The computed initial MA coefficients are not invertible
  You should induce invertibility, choose a different model order, or you can
  pass your own start_params.</li>
  <li>The computed initial AR coefficients are not stationary
  You should induce stationarity, choose a different model order, or you can
  pass your own start_params.</li>
  </ol>
  <p>Why does auto arima return model coefficients without an invertible MA or AR coefficients that aren't stationary? Are there setting in auto arima that i can set to avoid this issue in the future? Thanks</p>