This usually happens when there is an issue with the “CRON” set up on your web server. This is used to run scheduled background tasks that allow our plugin to update and show new posts.
To fix this, you can check with your web hosting company to see if the CRON configuration on your server is running correctly. Additionally, you can also check that WP_CRON is enabled in the wp-config.php file on your server. This article gives more information on that.
One other reason could be that your page cache lifetime (TTL) is too high, and this blocks the plugin from showing new posts. If you have a caching plugin on your site, check the TTL settings and set it to a lower rate.
Finally, check the “Caching” setting on the plugin; To do so, navigate to Instagram Feed > Settings > Feed > Caching. You can lower the time, so it checks for new posts faster.
If the steps above do not help, you could also try adding the property cachetime=30 to your shortcode this will use an alternate method of updating the feed. If your current shortcode is [instagram-feed feed="1"], you would change it to [instagram-feed feed="1" cachetime=30].