On Instagram, apparently you have got 5 min. to prove that your post is interesting!
Before the posts were shown in people's feed chronologically. Today, the new algorithm - like FB - decides to show your post to more followers, based on the level of interaction within the first 5 min to 1 hour max.
Instagram seems to be slowly limiting the impressions and reach that posts receive in view to inflate their advertising income.
To overcome that auto-censure from Instagram, there are PODs.
PODs are engagement groups where people there promise to share and comment on a link. They can be found on Instagram DM, Telegram, What's app etc.