I want to start an email service provider like gmail, outlook, protonmail

[joy223]

I want to start a paid email service provider. I have about 5 customers already who will sign up. I plan to charge 20 dollars a year for 1 email and 50GB of space.

I bought a domain. How can i get started?

will roundcube allow anyone who goes to my domain and register up. My plan is just to put on the domain homepage a link to paypal so they can pay 20USD then when i receive payment i will manually approve their email account.

I installed roundcube and i already see the login page. How do i access the admin panel so i can open up registration?

[Dmitry42]

Roundcube its just client like Outlook, Thunderbird.

So users and services part of your mail server you must create and setup independently form RC