Call your bank and ask them to allow “3D Secure e‑commerce” and international/AED e‑com on the same card. If you use a corporate card, the programme owner must whitelist the merchant category for government services.
Retry in an incognito window to avoid a stuck challenge iframe. If the page embeds 3DS in a frame, some content blockers break the handshake—disable them for this session only.
As a last resort, try another card on the same account holder or a virtual card with explicit online limit.