At least eight songs have "503" in the title – but none of them refer to the 503 error message.
503 – Dropout Kings (2018, the area code)
503 – Marduk (2015, the 503rd Heavy Panzer Battalion)
503 – OFF! (2012, a hospital room number)
503 – Geek Music (2018, a room number in The DaVinci Code)
503 – Hans Zimmer (2009, a room number in The DaVinci Code)
Hello 503 – Shape Of The Rain (1969, see below)
In The 503 – Lyberty/Kirko Bangz (2024, the area code)
Room 503 – Dusty Marcus/Shaine Derrick (2024, the site of a rendezvous)
Hello 503 refers to the depersonalization and robotification of humans in the age of technology. Charles Schulz acknowledged this depersonalization in 1963 by including a boy named 5 (short for 555) and his sisters 3 and 4 in several Peanuts strips. Their last name, 95472, is actually the ZIP Code for Sebastopol, the California city where Schulz lived.