Even though Instagram access tokens do not specify an expiration time, you should handle the case that either the user revokes access, or Instagram expires the token after some period of time. If the token is no longer valid, API responses will contain an “error_type=OAuthAccessTokenError”.
Instagram Access Token doesn’t normally expire at all, but you need to detect when they do and repeat your manual procedure to get a new one.
In this case, you will need to re-authenticate the user to obtain a new valid token.
If you constantly face Instagram authentication issue, please deactivate the BlossomThemes Instagram Feed and delete it.
After that, please download the Instagram plugin from this link – https://blossomthemes.com/wp-content/uploads/2019/04/blossomthemes-instagram-feed-3.0.0.zip
After the download is finished, upload the plugin via Admin Dashboard > Plugins > Add New > Upload and then activate the plugin.
In this plugin, you just need to add the username, no authentication is needed.