The snippet is two parts, the title and the description. You didn’t specify if one or both are not working so I’ve covered both. If the problem remains, please provide your website URL for further investigation.
SEO Title
A: What title did you enter for the page?
B: What title is output in the source code of your site?
C: What title does Google show?
Do A and B titles match? If not, please try the suggestions in this article: The SEO title output for the plugin doesn’t work as expected
Do A/B and C titles match? If not, please try the suggestions in this article: Google shows different titles for my site
SEO Description
A: What description did you enter for the page?
B: What description is output in the How To View The Page Source of Your Site“>source code of your site?
C: What description does Google show?
Do A and B descriptions match? If not, please try the suggestions in this article: I’m not seeing a meta description in my <head> section?
Do A/B and C descriptions match? If not, please try the suggestions in this article: My meta descriptions aren’t showing up in the search result pages
