Dear @MarieP
When you temporarily de-activate Yoast do the the problems go away?
Wordpress, Lay Theme & Laytheme's Addons are all up to date?
Any Custom CSS or JS that may interfere is temporarily removed.
And third-party plugins de-activated to see if this resolves the issue.
Regarding Yoast and meta tag:
http://laythemeforum.com:4567/topic/1883/meta-website-description-doesn-t-work/9
Best wishes Marie
Richard