Days not returning from function

I have this for TSLA to get the number of days:

days = security(NASDAQ:TSLA, D, barssince(start))

But it does not return anything.

When I try for other tickers like KRAKEN:ETHUSD it works fine. Why does it not work for TSLA?

Hi

What does it mean to return the number of days?
Probably because KRAKEN:ETHUSD quotes 24/7 and TSLA 8/5

Probably using the lookahead parameter would be smart

Documentation: https://www.tradingview.com/pine-script-reference/v4/#fun_security