The box
The box has gone offline
Check power, then the cable. Reporting and guest browsing are separate checks.
First, the important part: a box report is not proof that guest browsing is working. If it loses power, the Margovy page and capture stop working; what happens to any separate venue Wi-Fi depends on that venue network and is not changed by the box.
Check the power light. Cleaners and contractors unplug things more often than anything else does.
Check the cable from your router is seated at both ends, in the port marked 1.
Give it two minutes after power comes back. It has to reconnect before it reports in.
Still nothing? Unplug it for ten seconds and plug it back in.
Settings, then Wi-Fi and box, shows whether the box is reporting, or when it last did. The box reports in every two minutes, so a gap of more than about fifteen minutes means something is genuinely wrong. A box that has gone quiet shows as "Not reporting", which is also what a box looks like while it is in the post. If the steps above have not brought it back, ask in the chat button at the bottom of any dashboard page, or send us a message from the contact page.
If this did not solve it
Send us a message. Tell us the venue name and what you were doing when it went wrong, and a person will reply.