Google has been having a lot of indexing issues primarily affecting Google News publishers. The issue started a while back in 2019 and Google’s Danny Sullivan acknowledged the issue and said it was being diagnosed.
We're aware of some indexing issues with Google News content. It appears to involve a limited number of publishers. We're actively diagnosing the news issue now. This is not related to last week's indexing issue, which was resolved.
— Google SearchLiaison (@searchliaison) April 16, 2019
Clearly, this has been ongoing as until today, there are a lot of publishers crying out on dropped sites on Google News. There isn’t much that one can do until Google fixes the issue. Google Search and Google News index sites separately, as Google News is selective when choosing content that goes into their news aggregator.
This bug has affected a limited number of sites globally. Recently, Google announces the algorithm update which is expected to have rolled out by now. I suspect the Google News issues may have been triggered by core algorithm updates.
Newly accepted or approved websites on Google News should be indexed instantly but instead, there is a swarm of complaints about indexing issues on Google News.

Not so long ago, iBusiness was approved and added to the Publisher Centre. I may have popped expensive champagne early in celebration of such an accomplishment – however, it has been days without any inclusion in the news section and it seems iBusiness is also affected by the bug.

Speaking to Google Support Team, Google has acknowledged that it is aware of the issue, anyone who is unable to see their content on Google News, Google’s engineers are busy looking into it and we’ll get feedback in due time.

“Also, I can see that recently your publication named iBusiness.co.za was also approved in Google News. Please note that if you’re unable to see your content in news.google.com, we sincerely apologies for this. Our engineers are currently looking into this and will get back to at the earliest. ”
“Great news! We took a look at your content on Google News, and we seem to be indexing fresh content frequently from your site. I have attached a screenshot for your reference.”
The screenshot provided was using the string site: URL in the Google news section which I don’t find reliable.

We have a live account that isn’t indexing currently; however, we will remain patient and continue working twice as hard providing users with the best internet experience with our well written and informative news and articles.
THE UPDATE
As soon as we hear anything from Google we will keep you informed. There are some webmasters and publishers saying that being approved doesn’t guarantee that your articles will appear on Google News, I find this erroneous and I still stand to be corrected.
Some publishers blame the new Publisher Centre which was launched on the 10th of December 2019 and the previous partner dash center was closed or rather redirected to the new one. Every website that has been approved on the new Publisher Center is not showing on Google News.