I am getting a warning saying 'Something went wrong: Maximum hourly/flat rate exceeded' what does it mean?

This means that the shift that you are trying to publish is above the maximum rate (either by hourly or fixed rate) that your organisation allows. Please double check the rate that you have put in to ensure that there isn’t a typo. If you need to exceed this then you would need to check this internally as this has been set by your organisation.