Why is the site not in the search?

Question

Search Engine Optimization

hello, there was such a problem, for some time the site was in the top 10 for the main queries in Google and Yandex, sometimes it fell to 11-14th place, but it was always there. Attendance did not fall sharply, on average, always at the same level. I removed some keywords, put a few others, but the main thing remained. A few days ago I went into the search to check the positions, but it’s not there at all, it shows that it’s supposedly 15 on average, but it’s simply not at 15, nor at 30, nor at 150, it’s only there if you enter the site address, which can be a problem? could it be that a few key phrases not related to the search query could have affected