# Error 502

UTC

## Bad Gateway

### Browser
Working

### Maatma
Working

###
Error

### What happened?

Maatma is responding with this error page because we were not able to contact the host you want to access.

### It's my host, what can I do?

First, check that your tunnel is up on the Maatma's tunnels page.

If it's up, most probably there is no program configured to respond on the given port (check with `ss -tln`), or your firewall is filtering the request (check with `tcpdump` if you see the request and the answer).