Reverse proxy mode setup in New AIO instance in docker

The OS I am running is ubuntu 22.04. I’ve set my local dns record to resolve nextcloud. to my home lab’s external-facing IP. The following guides are the ones that I am following:

Here is my docker compose file:

version: "3"
    container_name: nextcloud-aio-mastercontainer
    image: nextcloud/all-in-one:latest
    restart: always
      - 8080:8080
      - APACHE_PORT=11000
      - NEXTCLOUD_DATADIR=/etc/nextcloud/data
      - nextcloud_aio_mastercontainer:/mnt/docker-aio-config
      - /var/run/docker.sock:/var/run/docker.sock:ro
    container_name: nginx
    image: nginx:1.21.6
    restart: always
      - 80:80
      - 443:443
      # - ./nginx:/etc/nginx
      - /etc/letsencrypt:/etc/letsencrypt

    name: nextcloud_aio_mastercontainer

The machine is on a lan, and has a private IP address.
On the nextcloud host, when I ping nextcloud., it resolves to my WAN’s public IP address. On the web gui, for the domain field, I enter nextcloud.. I view the log file for the aio docker container, and see the following:

NOTICE: PHP message: The response of the connection attempt to "https://nextcloud.<redacted>:443" was:
NOTICE: PHP message: Expected was: <redacted>
NOTICE: PHP message: The error message was: SSL certificate problem: self-signed certificate

I’m just not sure where to go from here.

NOTE: It seems there’s a parser messing with some of my text. Wherever you see “nextcloud.”, it should really read as follows:

Hi, do I see correctly that you do not own a domain?

I do own it.

I see. Can you follow all-in-one/ at main · nextcloud/all-in-one · GitHub then?

I looked in the aio log files, and didn’t see anything about /var/run/docker.sock in there.
When I attempt to drop into the caddy container to check #7 I get this:
docker exec -it 710a4beebfcc bash OCI runtime exec failed: exec failed: unable to start container process: exec: "bash": executable file not found in $PATH: unknown