KeyError: 'The `start` argument could not match a location related to the index of the data.' but when I check my indexes they do exist

Question

i try to predict usinf a SARIMAX model:

pred = seas_model_results.predict(start = test_df.index[0], end = train_df.index[-1])

However I get this error

KeyError: 'The start argument could not match a location related to the index of the data.' but when I check my indexes they do exist.

I have tried everything, and I have not been able to, it says that it does not match but I check the data frame and this date does exist.

I need to perform a comprehensive analysis of the performance of time series forecasts by generating forecasts, calculating the RMSE for their evaluation and visualizing the forecast versus actual values.

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