The eggs you bought could have been old, when buying eggs first test the eggs with a candeller to check there are no cracks in the eggs then secondly check how old the eggs are by placing the eggs in water. If the eggs rise and float upwards then they are old, if they lay flat on the bottom they are fresh.
I have a r-com 20 keep at 37.5 and humidity 45% but I would put a seperate thermometer inside as I find they are not 100% accurate.
Keep eggs that have been posted to you in a room for 24 hours to rest before incubating.
Sue