I have never used the website in question and I would avoid it even if it was working.
You should never use online websites for generating a bitcoin address.

If you want to have a bech32 bitcoin address, install a trustworthy open source wallet like electrum or Sparrow and create a wallet. In this way, you can have multiple addresses all generated from a seed phrase.
It's recommended to generate your wallet offline on an air-gapped device.