Error code 500 accessing secure sites

This article describes why you can get "Error response Error code 500. Message: Internal Server Error" when accessing any secure (https) site.

This error can happen when you use web acceleration software such as AT&T Worldnet Accelerator. While non-secure websites work with this software, secure websites do not. To solve the problem, you should configure Firefox to not use the web accelerator for https.

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the Advanced settings panel.
3. Click the Network tab.
4. Click Settings....
5. If Manual proxy configuration is selected, continue to the next step. If not, these instructions won't solve your problem.
6. Deselect Use this proxy server for all protocols.

• • If it's not selected, leave it as is.

1. Delete any text in the text box beside SSL Proxy:.
2. To the right of SSL Proxy:, set the Port: to 0.
3. Press OK.
4. Close the Settings page. Any changes you've made will automatically be saved. .