Your site loads slowly on a phone
How to check: Turn off Wi-Fi and open your site on mobile data. If the first screen takes over 3 seconds, this reason applies. For an exact measurement, use Google's free speed test: pagespeed.web.dev
What to fix: Compress images and load heavy content after the first screen appears. The design stays the same.
Demo example: On a roofing company site, the main image on a phone now appears in 0.7 s instead of 19.7 s. Page size dropped from 4.3 MB to 84 KB.