How to fix DNS_PROBE_FINISHED_NXDOMAIN for my domain

I recently set up Traefik for my Django App pointing two subdomains to one IP.
Everything was working fine, Traefik managed SSL certificates for this two subdomains but suddenly my users started having sporadic DNS_PROBE_FINISHED_NXDOMAIN.

I consulted my VPS provider (and where i've managed the DNS records) and they said everything was configured correctly.

I am really lost and don't know what to do to fix this, please help!

Here I show my configuration:

Django app

context: .
- 8000:8000
- ./app:/app
command: >
sh -c "python migrate &&
python collectstatic --no-input &&
gunicorn --bind app.wsgi"
- ./.env
- db
- traefik.enable=true

image: traefik:v2.3
- 80:80
- 443:443
restart: always
- /var/run/docker.sock:/var/run/docker.sock:ro
- ./traefik/traefik.toml:/etc/traefik/traefik.toml
- traefik-public-certificates:/certificates


According to the error name and Google search this is a DNS issue, has nothing to do with the proxy or webserver.

DNS_PROBE_FINISHED_NXDOMAIN error appears when the domain name system cannot resolve a website’s URL into an IP address, making the web browser unable to reach it. The NXDOMAIN in the error code implies that the domain is non-existent.

Random source

But the domains indeed exists and they both point to the same IP, do you know where should I focus my efforts? I am also having an sporadic ERR_NAME_NOT_RESOLVED error

First, check your internet connection to ensure it is stable. Then, clear your browser cache and restart the browser. If the issue persists, flush the DNS cache by using the appropriate command in the command prompt or terminal. Changing your DNS servers to providers like Google DNS or OpenDNS may also help. Additionally, disable any VPN or proxy services you're using and restart your router. If none of these steps work, it may be necessary to contact the website administrator or your internet service provider for further assistance.