SpaceX aborts third attempt of Starlink v1.0 Launch 12

The Starlink v1.0 Launch 12 mission aborted at T-18 seconds due to a ground sensor issue on Thursday morning from LC-39A at Kennedy Space Center. This was the third attempt to get the mission off the ground. During the previous launch attempt on September 28th, the Falcon 9 was fueled and the countdown proceeded to T- 31 seconds, when a scrub was called due to weather. The mission then had to wait for the range to become available again as the NROL-44 mission had priority. More

(Source: NASASpaceFlight.com - Oct 1)