The site cannot find my wallet

Work down this list:

• Sign in to your Creta account first — connecting a wallet is refused until you are signed in.
• Check the Creta Wallet extension is installed and enabled on your browser's extensions page.
• Reload the page. A tab opened before you installed the extension cannot see it.
• Open the extension and unlock it, then connect again.
• Use Chrome or another Chromium browser — the extension cannot load in Firefox or Safari, and cannot be installed on a phone at all.

One case that looks like a bug: Creta sites look for the wallet by its Web Store extension id, so a copy loaded by hand as an unpacked folder will never be found.