Despite strong quarterly results, Zscaler's outlook wasn't strong enough to support its valuation.Shares of Zscaler (ZS 0.73%) fell 20.4% in March, according to data provided by S&P Global Market Intelligence. Despite delivering impressive quarterly financial results, the cybersecurity stock still slid lower thanks to a combination of pessimism about its outlook, an expensive valuation, and unfavorable market conditions.Zscaler's quarterly results were solid, but its outlook was less impressiveZscaler repor ...