This is the both-rails-blocked case, and we have seen it reported from Pakistan: debit cards from two different banks refused at OpenRouter's checkout even after both banks confirmed international payments were enabled, USDC bought in order to pay another way, and then a 403 on OpenRouter's crypto checkout.
We cannot tell you what that 403 means, and neither can anyone else outside OpenRouter — so the 403 itself belongs in a ticket with their support. What you can check is something narrower: whether OpenRouter still issues you a payment link for the amount you want. That link is the prerequisite for paying outside OpenRouter's own checkout, ours included. If no link is issued, or your account or organisation is flagged, no payment route changes that (see our article on an account banned or region-restricted after paying).
If you have a payment link, ROZO Checkout settles it with USDC, USDT, BTC Lightning and other supported coins for a 1% service fee, with no card step. Already holding the coin is the whole precondition — there is nothing else to buy. It does not fix the card declines and it does not lift an account restriction. ROZO is independent and not affiliated with OpenRouter or Coinbase.