If you are planning to use ProcessMaker in production, then do a manual install.
Bitnami can work on a server, but if you already have Apache and MySQL installed, then it installed them on nonstandard ports.
Bitnami tells you which ports it used when it installed. For example, if Apache was already installed on the server, then Bitnami probably used port 8080, so you can login to ProcessMaker by using the web browser to go to the server's addess with ":8080" appended.
You may have a firewall blocking port 8080, so you should check whether that is the problem. You should also check whether the firewall is blocking the port used by MySQL.
Since you didn't mention what operating system your server is using, it is hard for me to help you debug the problem.
Amos B. Batto ♦ Independent BPM consultant ♦ email: amosbatto[at]yahoo[dot]com
(former ProcessMaker Forum Manager between May 2009 and September 2019)