Cannot access Magento software in a web browser

Symptom: The following message displays when you try to access the Magento storefront or Admin:

Whoops, it looks like you have an invalid PHP version.
Magento supports PHP 5.5 or newer.

Solution

Either upgrade PHP or restart Apache (Apache might not be using the same PHP version as is on the file system).

Symptom: A 404 (Not Found) error displays.

Solution

Try the following:

• Make sure Apache server rewrites are enabled.

  If Apache server rewrites are set incorrectly, static files aren’t served from the correct location.

• Likely an issue with the base URL you entered during the installation. You specify the base URL as the value of --base-url= when installing Magento from the command line or as the value of the Your Store Address field on the Web Configuration page of the web installer.

  The base URL must start with the scheme (such as http://) and end with a trailing slash (/). Run the installer again with a valid value and try accessing Magento afterward.

  To restart Apache:

  • Ubuntu: service apache2 restart
  • CentOS: service httpd restart