URLs not appeared on Google Search!

Hi. Do you know sometimes URLs now appeared, now disappeared on Google Search?
Ex: When i search Hue City Tour, sometimes my this URL https://adventurejourney.vn/private-day-tours/hue-city-tour-1-day.html appeared and disappeared.
Highly appreciate your support!

hey there

Well, this is not a theme related problem, this is how to google search work. my suggestion is to install and properly configure SEO plugin on your website