Can't run site under subdomain, need to declare it in .env

I don't know how to declare my subdomain in the .env file, whenever I try to run my webapp, this pops up:

Install is ok. But looks like you are running the site under subdomain.
When you run the site in subdomain, you need to declare that subdomain in the .env file

IGNORE_SUBDOMAINS="www,app"

I feel it is as easy as putting the subdomains in the .env file, but I don't knwo how to proceed. Any help I would really appreciate it!

Here is my .env file:

APP_NAME='secret'
APP_PROJECT_TYPE=qrsaas
APP_ENV=local
APP_KEY=base64:secret=
APP_DEBUG=true
APP_LOG_LEVEL=debug
APP_URL=http://127.0.0.1
APP_LOCALE=EN
IGNORE_SUBDOMAINS="www,127,2708779e7b46,51"
TIME_ZONE="Europe/Berlin"
CASHIER_CURRENCY=EUR
APP_DEV=true
DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=secret
DB_USERNAME=secret
DB_PASSWORD=secret

The site is running on Laravel.

via Chebli Mohamed