A blocked access message in Website Kiosk usually means the page being opened, or one of its redirect destinations, is not included in the allowed URLs.
Check the URL behavior outside kiosk first if possible. If the initial URL redirects to another path, both the original URL and the redirected URL must be allowed.
For example, if the web app starts at: https://<domain>/<path>/
but redirects to: https://<domain>/<another-path>/
add both URLs to the allowlist in Website Kiosk Settings. If the URL path requires a trailing slash, include it exactly as used by the site. For URLs with query parameters, use the complete URL provided by the web app/vendor and avoid adding an extra slash after the query string unless the site specifically requires it.
As a quick test, removing the allowlist temporarily can confirm whether the issue is caused by URL filtering or by the web app itself. If the page loads without the allowlist, add back the required original and redirect URLs one by one.