Could be… hard to tell without more details. Fully Kiosk uses the ‘webview’ bundled with the system. So if that webview is running version 85 or newer, it would be impacted by the mixed content issue (HTTP image on HTTPS page)… or if it’s running 111 or newer, it would be impacted by the local IP limitation.
Both are discussed in detail in the posts above including workarounds for both.