The URL is not accessible when installing Magento

When installing Magento, we may get such error "The URL is not accessible".

In some earlier versions of Magento, we can fix this problem by change code of app/code/core/Mage/Install/Model/Installer/Config.php
Just change

to

Will solve the problem. It's because that the URL rewriting doesn't work for some reasons. (Magento uses .htaccess files to add URL rewriting rules)

 

But in Magento 1.9, checking the "Skip the base url validation" option will solve this problem

Authorize.net payment not shown in Magento checkout page

There are mainly two reasons causing that Authorize.net payment method not showing in Magento checkout page

 

The Mage_Authorizenet and Mage_Payment module is not enabled

In Admin page, go to System->Configuration menu. In Advanced->Advanced section at left panel, enable the "Mage_Authorizenet" and "Mage_Payment" module.

 

The magento currency is not same as Authorize.net currency

Assume you are using US Dollar as your currency.

In Admin page go to System->Configuration menu. In General->Currency Setup section, set the Base Currency and Default Display Currency to "US Dollar". Then go to Sales->Payment Methods section, under Authorize.net (or Direct Post) tab, change the Accepted Currency to "US Dollar".