I don’t see any field to write a message when I open the widget. Correct if you haven’t identified yourself yet (section 4) — the internal widget offers no chat at all without a session, unlike the public widget.
The “Log in” button stays disabled. Fill in both fields, email and password — it only enables once both have content.
I have no way to enter the two-factor verification code. Turn it on first in Settings → Security (Manual 26, section 5) — it’s an unavoidable requirement to enter the internal widget.
A real customer reached the internal widget’s link and sees an error. That’s the expected behavior: an instance marked internal never serves the public. Use another (public) instance for the link/snippet you share with customers.
Does the internal widget count as “Channel-linked access”? No — they’re different mechanisms, even though both require two-factor verification (section 2). The internal widget is a chat window with its own login; “Channel-linked access” (Manual 51) links your personal WhatsApp/Telegram.