Page got deindexed

[interfero]

Hello, guys. Registered here just to ask about the issue I have:
I had a page that was on top 2 position for several months (content is good and a few nice in-content links are referring to this specific page).
Yesterday I checked SERP again as I do on regular basis and the page wasn't there (the day before it was, so it happened Sep 24th). And not just at the top, but NOWHERE.
I went to search console to check that URL and it says that the url is not in Google's index (page has been crawled but not indexed yet).

What's wrong and what can I do?
Thanks in advance

[goodroi]

First, I'd search a few text strings from the page to see if anything else is found. Maybe another site stole the content & republished it. Doubtful but it's easy to do so that is where I start. If there isn't a large amount of unique & valuable information on the page, it is time to redo the page. Google has become pickier about what pages they keep in the index. Make sure to circumvent Google's personalized search results by using a fresh browser/virtual device.

Second, check out Google's search console to see if there is any information or noticeable trends.

Third, check out that Google can crawl the page. Is robots.txt ok? Is htaccess configured properly? Are the meta tags good? Are there plenty of links pointing to the page?

Fourth, do a deep dive in the log file. When did googlebot last visit the page and what happened. Was it all 200 or was there some 400, 500 or other weird trouble? Was anything changed that could make Google blind to the content (javascript, ajax, flash, paywall, etc).

PS It could also be a temporary glitch as Google switches their index across datacenters during updates.

[TalkativeEditorial]

Happening to a lot of people at the moment. That and many other issues. It's probably not your fault.

[Jori]

Simply ask google to reindex it with gsc, and cross fingers...

[interfero]

Guys, thank you for all your answers.

To make it clear:
1) The website is ok, that's the only page which was deindexed. Coincidence or not, that page was the most the most valuable.
2) The page is COMPLETELY gone from Google's search, even if I search by full url - the page won't show up.
3) I tried to manually index it via GSC - doesn't work.

I wonder, may it be caused by fake DMCA complaint from my competitor? But I didn't receive any notifications, no manual actions and the content is absolutely unique (that's why it was in top for a long time).