jks

From the CHANGE_LOG file:

v1.387  April 10, 2020
    Admin page control tab:
        By special request, added ability to limit number of simultaneous non-Kiwi API connections
            (e.g. kiwirecorder). This works in the same way (and overrides) the TDoA extension
            setting that limits the number of simultaneous TDoA connections.
    DX label edit:
        Passband frequencies can be entered using "k" and "M" suffixes for kHz and MHz.
        I.e. "2100" and "2.1k" are equivalent, as are "1200000", "1200k" and "1.2M".
        However subsequent display of the passband field is always in Hz.
        So after entering "-2.1k, 1.2M" on the next edit the field will display "-2100, 1200000" (Hz).

Yep. Currently the ITU region setting only has effect for defining the NDB band bar and the 80/75m band overlap (which has problems of its own). It is not used for 160m (Fstart), 40/41m, 30m (Fstop) etc.

Is this Kiwi available from the Internet so I could connect (I don't need any passwords) and take a look?
"Being available" doesn't mean it has to be a publicly listed Kiwi. Only that port 8073 on your router is set to map to the Kiwi and that you can tell me your public ip address.

Oh yes, and based on recent experience I guess we now have to ask you: is your ISP Comcast?

Also, is there WiFi involved anywhere in the path between your Kiwi and the machine running the browser? Does the same thing happen on some other device like a tablet, cellphone etc?

I know this sounds like entry-level tech support, but seriously, try power cycling all your network equipment. I used to have a WiFi bridge connection between my development Kiwis and my laptop due to the physical setup here. About twice a year my Internet router or the TP-Link bridge would lose its mind and the ping times randomly go to several seconds for no apparent reason. Power cycle fixed it, but only after half my hair had already been pulled out trying to find out what was wrong with my code. Needless to say I found a way to run an Ethernet cable.

but it still doesn't show up on the map

Which map? rx.linkfanel.net (aka map.kiwisdr.com)? Or the map section of sdr.hu?
If your Kiwi is listed on kiwisdr.com/public (aka rx.kiwisdr.com) then it should appear on the rx.linkfanel.net map since the kiwisdr.com listing site is where linkfanel.net gets its data from currently.

As you point out sdr.hu is an entirely independent (and now optional) registration path. It is quite possible that there might be an intermittent connection issue with sdr.hu, yet people are still finding your Kiwi via {rx,map}.kiwisdr.com rather than saved browser history.

What exact error message is sdr.hu returning in the log when the registration attempts from your Kiwi fail?

Update: I'll answer my own question. Your Kiwi is reporting this:

Wed Apr  1 01:57:01 00:49:07.685 ....      sdr.hu registration: DOWN

So that's a problem we've seen from sdr.hu before. And it's something Andras will have to fix since we have no control over his site.

At the moment I can't connect to http://71.197.249.8:8073
It just times out. If you hover over your purple icon on rx.linkfanel.net it says "Last online: 7 hours ago".

So I think you've got incoming connectivity problems. Now I was able to get in fine an hour ago to check your log messages. So it hasn't been completely down. On the admin "network" tab if you click the "check open port" button do you get a status of "YES" to either of those paths? That button makes a request to kiwisdr.com to check connectivity to your Kiwi (in the incoming direction) using both the DNS-based and IP-based paths.