[Plugin: WordPress SEO by Yoast] Facebook description showing code

I used this plugin long time. But today I getting error make me crazy.

Instead of displaying meta content, facebook description now displaying code.

https://content.screencast.com/users/HungSzczesny/folders/Loi%20trong%20qua%20trinh%20lam%20Wordpress/media/ce33d5c5-150e-45c7-90da-091cefd88199/Untitled.png

Hope anyone can help me. Thank in advance!