Looks like Cloudflare's Ethereum Gateway is having some issues.
<summary>Advanced options</summary>
<div class="details-body inline-input-container">
<label for="rpc">JSON-RPC node:</label>
- <input type="url" name="rpc" id="rpc" value="https://eth.ardis.lu/v1/mainnet" required>
+ <input type="url" name="rpc" id="rpc" value="https://ethereum-rpc.publicnode.com" required>
</div>
<div class="details-body inline-input-container">
<label for="block">Block number (empty value will default to "latest"):</label>