In the first 2-3 cycles kegg is learning your unique cycle trends. kegg relies on the user providing consistent data, which is taking readings throughout the cycle at a consistent time of day. In the first cycle, kegg will place a best-guess prediction based on the information provided by the user during their account setup. If the length of your cycle varies significantly,* it may take more time for kegg to learn your cycle trends. While kegg is learning, or if you are having an irregular cycle due to stress, travel, or illness, you can watch for downward trends and have sex on days with descending readings to maximize your chance of conception.
*kegg is best suited for users with regular cycles that are more than 21 days long and do not exceed 40 days. If you have cycles shorter than 21 days or longer than 40 days, a fertile window prediction will not be displayed.