This post will give you a glimpse of how I got approved/rejected from the Facebook Instant Articles. You will know the result (I will edit this post) after the final edit of this post.
I have been trying to get my website into Facebook Instant Articles from past 4 days. I am using the official Facebook/Automattic WordPress plugin for Instant Article setup. The installation and configuration was fine, except a "permission error" appeared on the WordPress configuration page for this feature. Later I have solved it by configuring and submitting through my Facebook Page > Publishing Tools > Instant Articles > Configuration window.
When I have published 8 post on the website, I have applied (Submitted for review) and waited for the notification from the review team. You won't get notification for your approval or rejection. After 2 days, I have checked the Publisher Tools > Instant Articles > Configuration of my Page on Facebook (Desktop version), the team left me an alert that said I had an error on my articles. It was related to the embedding inside articles. There was an example article (link to the Instant Article source code for that article) of mine. And, there was an image, which had 2 screenshots side by side. It looked like the current screenshot and screenshot (from their side) after the solution.
What I did?
There was a Twitter embed on that post and I thought it was causing an issue. I was directly copying the Twitter embed code from their website and pasting into the "Text" (not Visual) editor of WordPress dashboard within the article. In order to solve this issue, I have deleted the embed code and re-pasted the Tweet URL (nor embed code) into the "Visual" editor of the dashboard. Now, the Tweet gets automatically embedded because of WordPress' automatic embed feature.
Now, when I checked it in the Page Manager app, it looked fine. I have also checked the source code of the article from the error message given by the review team. There was an <iframe> code. Here's the code:
<figure class="op-interactive"><iframe class="no-margin">
<blockquote class="twitter-tweet" data-width="550">
Tweet details </blockquote>
<p><script async="" src="//platform.twitter.com/widgets.js" charset="utf-8"></script></p></iframe></figure>
So, I have Submitted for the review and waited for 2 more days and once again, my Instant Articles application was rejected for the same reason with another screenshot where the Tweet image was showing up and no texts of the Tweet. However, from my Page Manager app, article is formatted and showing up correctly. Now, after writing this post here, I will remove the Twitter embed code (I will just add a link to the Tweet for any anchor text) and I will submit for review. Stay tuned, I will keep you updated.
Update 1 (same day): After I submitted for approval, I have gone through an article about <op-social> tag depreciated to <op-interactive> by Facebook, which showed an example code like this:
<!-- Don't do this. Missing width and height. -->
My <iframe> code was not adding any size width or height). It was automatically done by the official plugin, so, I have removed the embed of the article and just linked the Twitter URL to an "Anchor Text." I think, this problem should be solved by an update by the Plugin developer. Let's wait for the Review Team.