I installed Apache and then PHPMyAdmin on my Ubuntu server, but I have not been able to access PHPMyAdmin at
http://localhost is working however.
What errors did the error logs (access and or error logs)? That would help determining the issue. Could be a socket issue, but could be a url issue too. I assume PHP is installed too?
You'll need an Ubuntu server with initial setup and a LAMP Server
If you haven't installed the LAMP Server. You can follow the steps on the below link to install it.
Then Install the phpMyAdmin in your server. Follow the steps on the link below.
Did you install MySQL?
Another possibility is to download phpmyadmin and extract is to htdocs/phpmyadmin.
If you are trying to open
http://localhost/phpmyadmin/ and getting 404 Error then follow steps.
sudo nano /etc/apache2/apache2.conf
Add the phpmyadmin config to the file:
then restart apache:
sudo service apache2 restart