Need help on Google Analytics

Hi experts,

Can anyone tell me what is engaged session and event count in GA?

and if the data shows in red mark then what will be the reason for event count and engage session goes down?

Pls can anyone help me ?

AFAIK engaged session is a session that lasts for more than 5 seconds (or maybe not 5 seconds specifically, but for a pre-set duration of time... I don't know what the preset is, though).

Event counts are actions that people do on your site, such as free signups, clicks on affiliate links, downloads, etc...