I've just tried to reproduce the issue but I haven't been able to do it. I launched a BCH instance with WordPress multisite and PHP 5.6 and I modified the main domain of the site using our configuration tool and everything is fine and I can access the site properly. I also tested that I can access phpMyAdmin without problems.
As I mentioned, the best way to configure the domain of WordPress Multisite is using the configuration tool that Bitnami provides. You can find more information about it in the documentation
I also checked that you have performed changes in the configuration files of Apache and WordPress, please note that our configuration tool also modifies some fields in the database that are required when modifying the default domain of WordPress.
I also noticed that your site is not accessible right now, did you perform any change in the configuration files of WordPress or Apache?
There are some information that you didn't share with us, could you please let us know the following information?
I let you know how to access the database, did you try to access it? did you receive any error message? Could you please share a screenshot of it?
- I also asked for the mysql and apache logs, could you please send them to me at jota [at] bitnami [dot] com?
I think this is taking so much time so I suggest you do the next steps. You'll start all the process again but I think that it's the best idea as you'll have your server updated to the latest version:
- As mentioned in this post
create a backup of the database of the original server and launch a new one.
- Drop and recover the database in the new instance and create a new one using the commands that I mentioned in the previous post.
IMPORTANT: check the wp-config.php file of the new instance to set the password correctly when creating the new database.
- Update the domain of the main site following our documentation
Please, if you have any questions, don't hesitate to ask.