CTR is stable, impression / clicksimpressions means amount of times that your pages showed up in google.
active users I don't know what it means, but it's probably people that visited your site
So, based on these 2 definitions it looks like your site shows up in google but people don't want to click on it for whatever reason. So, you gotta figure out the reason and fix it
Thanks for the idea but I checked various kws and the site appears normallyIf I had to guess, your website might be hacked or people simply cannot get to your website from some other tecnical reason. Try inkognito browser mode, type your website + some keyword and see whether you're able to get at your website like this.