How do I fix the "It seems like you are trying to send this twice" error when logging into my Epic Games account?

This error can be fixed by clearing your cache from your web browser. 

Here are steps for some browsers to do this.

Google Chrome

1. Open Chrome.
2. At the top right, click the three dots.
3. Click More tools, and then click Clear browsing data.
4. At the top, select All time.
5. Check the boxes next to Cookies and other site data and Cached images and files.
6. Click Clear data.

Mozilla Firefox

1. Click the menu button, and then select Options.
2. Select the Privacy & Security panel.
3. In the Cookies and Site Data section, click Clear Data….
4. With both checkboxes checked, click the Clear button.

Safari

1. Open Safari.
2. Click History.
3. Click Clear History.
4. Make sure to select All History and click Clear History.