ESPHome WebUI won't load

I’m trying to install ESPHome, following the directions on https://esphome.io/ but am getting stuck.

You should now be greeted by a nice introduction wizard which will step you through creating your first configuration.

The wizard never loads, eventually timing out with a 501.

I’m not sure where to go from here.

Thanks in advance.

ESPHome Log:

[s6-init] making user provided files available at /var/run/s6/etc...exited 0.
[s6-init] ensuring user provided files have correct perms...exited 0.
[fix-attrs.d] applying ownership & permissions fixes...
[fix-attrs.d] done.
[cont-init.d] executing container initialization scripts...
[cont-init.d] 00-banner.sh: executing... 

-----------------------------------------------------------
 Hass.io Add-on: ESPHome
 ESPHome Hass.io add-on for intelligently managing all your ESP8266/ESP32 devices.
-----------------------------------------------------------
 Add-on version: 1.14.3
 You are running the latest version of this add-on.
 System: Ubuntu 16.04.6 LTS  (amd64 / intel-nuc)
 Home Assistant version: 0.102.2
 Supervisor version: 192
-----------------------------------------------------------
 Please, share the above information when looking for help
 or support in, e.g., GitHub, forums or the Discord chat.
-----------------------------------------------------------
[cont-init.d] 00-banner.sh: exited 0.
[cont-init.d] 01-log-level.sh: executing... 
[cont-init.d] 01-log-level.sh: exited 0.
[cont-init.d] 10-requirements.sh: executing... 
[cont-init.d] 10-requirements.sh: exited 0.
[cont-init.d] 20-nginx.sh: executing... 
[cont-init.d] 20-nginx.sh: exited 0.
[cont-init.d] 30-esphome.sh: executing... 
[cont-init.d] 30-esphome.sh: exited 0.
[cont-init.d] 40-migrate.sh: executing... 
[cont-init.d] 40-migrate.sh: exited 0.
[cont-init.d] done.
[services.d] starting services
[services.d] done.
[14:33:22] INFO: Waiting for dashboard to come up...
[14:33:22] INFO: Starting ESPHome dashboard...
INFO Starting dashboard web server on unix socket /var/run/esphome.sock and configuration dir /config/esphome...
[14:33:22] INFO: Starting NGINX...

Which instructions? The docker ones, the hassio addon ones or the pip install ones?

The hassio addon

Anybody ever get a fix??