Share on facebook feature returns an error

Tested on XE 7.4.2 / Windows 8.1, Windows 7.

1. Create a Forum and a topic in it.
2. Open the topic page and share it on Facebook.

Actual result:

• After you click on the blue icon, you get a new facebook window containing the post you will share (I was already logged in on Facebook)
• If you click on Share button, you get: Sorry, this feature isn't available right now: An error occurred while processing this request. Please try again later.

Expected result:

• I expect to share the topic on my facebook chronology page.