Common with squash. Sounds like you only had male flowers and not female (easy to tell the difference just google it) .....or no bees to pollinate. Plant something that draws bees (if spotted horsemint grows in your area - it's a magnet for all kinds of bees - I keep one in my garden). Draw the bees. Until then you can use an artist's soft paint brush to pollinate yourself. Normally, the male blooms are first and sometimes the bees get all the pollen before there are female blossoms out.