A Creta site cannot find my wallet

Work down this list:

• Check the extension is installed and enabled on your browser's extensions page — a disabled extension is invisible to every site.
• Reload the page. The wallet announces itself as the page loads, so a tab opened before you installed it will not see it.
• Open the wallet and unlock it, then try again.
• If you use several wallet extensions, another one may have claimed the connection first. Disable the others and reload.
• Check you are in a Chromium browser — the extension cannot load in Firefox or Safari.

One case that looks like a bug and is not: Creta sites look for the wallet by its Web Store extension id, so a copy loaded by hand as an unpacked folder has a different id and will never be found. Install it from the Web Store listing.