I had never used Yandex until one day my analytics started showing about 30 visits a day from yandex/organic. My site is multilingual and has both Russian and English content, and hosted on .com domain. All the Yandex traffic was going to my English pages though. I found that only 7 pages had been indexed, among the thousands of pages that my site has. So I set up Webmaster Tools on Yandex, and submitted a sitemap, the same one I submit to Google. Well, what happened is that after a few weeks I only had 3 pages indexed on Yandex, and my traffic from them went down. The sitemap verified okay on the Yandex sitemap verification tool. Has anybody had similar problems getting Yandex to index their site? Does anybody have any idea what could have gone wrong? My sitemap is fine because it works for google, is automatically generated by the backend of my site, so all of the pages are live, and site speed is only 3 seconds total load time per page.
I often use Yandex. Do You have repetitive content on site? Yandex usually deletes repetitive content. And check your robots.txt file.