Google Search Console: Too many pages in Crawled - currently not indexed section (more then 80%)

[gandreyev]

Dear SEO experts.

We have a math site https://mathematics-at-school.com
Running on Joomla 3.10.4. The site' age is more than 6 years.
Added more than 1000 articles (mainly math worksheets) and JavaScript interactive tests.
Sitemap is set up, crawl-able, added to GSC property.
Site indexable, no noindex tags.
Social profiles set up and linking to the website.

We noticed that many of pages are stacked in Crawled - currently not indexed section. Total number is about 890 pages. It is lasting long time (more than a year).

There are examples of these pages:
https://mathematics-at-school.com/multi ... pdf-or-jpg

https://mathematics-at-school.com/multi ... pdf-or-jpg

https://mathematics-at-school.com/grade ... pdf-or-jpg

https://mathematics-at-school.com/grade ... s-up-to-50

https://mathematics-at-school.com/multi ... pdf-or-jpg

We have read several articles about this situation, but do not exactly understand, why so many pages are in this section of Google Search Console?
We need any idea to "force" the pages to be indexed.
Thanks ahead for any help.

[pe7er]

I've checked the first link of the examples you gave.

Opening the HTML source of that page takes very much time.
And Google Lighthouse (option in Google Chrome browser) shows that the performance of that page is not good:

Screenshot from 2021-12-21 11-25-42.png

Could it be that the bad speed performance of some of your pages causes the issue?

[gandreyev]

Peter, thank you for replay.
At the beginig, the site was hosted on VPS server. And the location was in Moscow (for last 5 years). The speed was good. But the troubles with the indexation were the same.
A month ago, during black friday, we transfered the site to US hosting, because the target users are in the US. And we hoped, may be the indexation troubles would be solved after transferring. No, the trouble is NOT solved.
We are going to change the site template to simples one to speed up the site. Right now we using not fast template.

[Leftfield]

A problem might exist in how long your URLs are. I don't think these long URLs can help crawler, on the contrary. I would definitely recommend to edit them and make them shorter.

[gandreyev]

Hm, curious idea Never think about this.
For an experiment we will publish 3-4 articles with short urls.
Thanks for idea.

[kevinsolvify]

You could "force" the URL's to crawl in GSC. When in logged in Review a URL at https://yoururl.com at the top.
1. Enter URL
2. It'll say something like URL not found on Google so you just enter requests indexing just give it a day or two.

Works for me but you can only request up to 10 pages per day.