On literally the worst night to pass through the North Atlantic, The Californian stopped due to the icy conditions. The nearby Titanic had been warned, however, they were trying to contact Cape Race. As far as they were, they were the nearest land communication, and the Titanic needed to catch up on telegram messages. They had already been warned, so they brushed off this warning.
Unfortunately, it was a moonlit night full of stars. The waters were calm, and the conditions made iceberg spotting nearly impossible. Tragically, they spotted one about 40 seconds before impact. They didn't know it yet, but they had 2 hours and 40 minutes as the ship sank.
They sent out distress calls, and they shot off emergency flares. There were many ships in the North Atlantic at the time, including the Titanic's sister Olympic, who was over 500 nautical miles away. Unfortunately, the nearby Californian's sole telegram operator was off for the night. They noticed the flares, but they thought they were seeing fireworks.
The Carpathia was about 58 nautical miles away when she received the distress calls. It was all hands on deck. The Carpathia was known to go as fast as 14 knots, but that night she kicked it up to 17 knots. The ship arrived about 4am. After the survivors boarded, and the sun came up, they realized what they sailed through.