Zoom Video Communications Inc. fell the most in more than three weeks on Tuesday after third-quarter results brought the high-flying stock rally to an abrupt halt.

Analysts questioned whether the video-conferencing company’s momentum can be sustained once the pandemic begins to subside and more people return to working in offices and traveling to visit friends and families.

“Given the elevated expectations heading into the print, and the fear around what a post-Covid growth rate may look like for the company, we would expect near-term share weakness to persist,” RBC Capital Markets analyst Alex Zukin wrote in a note Tuesday.

Zoom on Monday gave a revenue forecast for the current quarter that topped analysts’ estimates but suggested a drop in its explosive growth, highlighting investors’ concerns that 2021 won’t be as favorable for the software maker as this year.

Zoom’s valuation, with a price-to-earnings ratio above 270, is “stretched” in light of the uncertainty for fiscal 2022 growth, Piper Sandler said.

Shares (ZM) closed down 15% on Tuesday, the biggest drop since Nov. 9. Even with that drop, the stock is up nearly 500% this year.