I have app still in development on Hostgator server and it is done registration and e-mail validation by default. Hostgator is filtering messages and not sending. After a support calls back and forth, they responded:

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Thank you for the clarification. After further testing, it would appear the script is not configured in a manner which will permit mail sending from our server. The script appears to be sending from localhost as the HELO name (or 127.0.0.1). 2022-03-20 13:20:15 1nW0A3-000gFe-3g <= admin@*****.com H=gator4322.hostgator.com ([127.0.0.1]) [162.241.***.***]:59380 Our servers will not permit mail to be sent from the localhost in the interest of security. In order for messages to get through, it will need to be sent from the primary IP of the server or you can simply use your domain in its place, so long as that domain is pointed to your server.

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my .env config is

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APP_ENV=production
APP_URL=http://dev.*****.com
...
MAIL_MAILER=smtp
MAIL_HOST=gator4322.hostgator.com
MAIL_PORT=465
MAIL_USERNAME=admin@******.com
MAIL_PASSWORD=*********
MAIL_ENCRYPTION=ssl
MAIL_FROM_ADDRESS=admin@*****.com
MAIL_FROM_NAME="${APP_NAME}"

Is there anywhere in the code where there is set a locahost where I should change to a domain name? Just to point out: there is no error, just that mail does not leave hostgator server.