Printing from the browser: permissions and certificates
Symptom: the POS runs in a browser and can't reach the printer — the scan finds nothing, or the same printer prints from the desktop app but not from the browser tab.
Allow local network access
Chrome and Edge ask permission before a website may talk to a device on your network. If that prompt was dismissed, every attempt fails silently.
Click the icon at the left of the address bar → Site settings → set Local network to Allow, then reload the page and scan again.
Mixed content
A POS served over https:// cannot open a plain http:// connection to a printer. Chrome and Edge allow it once you've granted local network access; other browsers block it outright. If your store runs on HTTPS and the printer only speaks HTTP, use the desktop app.
The printer's certificate
Printers secure themselves with their own certificate, which no browser trusts by default — the connection fails before it starts. Open https://printer-ip in the same browser once, accept the warning, and go back to the POS. You'll need to do this on each computer.
The desktop app doesn't have this problem: it accepts the printer's certificate itself, which is why the same printer works there and not in the tab.
Safari and Firefox
Neither has any of these routes. They have no local network permission to grant, and no support for USB or Bluetooth printers from a web page. On those browsers use a Wi-Fi printer that matches your store's HTTP or HTTPS, or use the desktop app.
Still stuck?
Use Copy setup report on the trouble screen and paste it into your message — it records which browser and which lane were tried.