This warning appears in rare cases when you undertake a schedule calculation for the first time, use a manually entered address as starting location, have created new customers or appointments or changed addresses. portatour® uses up-to-date road maps for route-optimization and calculates the real road distances and travel times between all customers. Example: 500 customers require 250.000 (=500x500) calculations on the server, which take some time. Thus, it may happen that during the calculation of your schedule these distance calculations are not completely finished yet, and therefore approximate distances and times based on beelines are provided. Depending on the percentage of beelines, the schedule quality can be decisively influenced. We recommend to wait for the exact distance calculation on the server to be finished and to restart the schedule calculation after a few minutes.