When you first create the Instagram Access token, you need to keep in mind that the token will be valid only for 60days. If the Token is not refreshed, the Instagram Feed module will stop working.
Refresh the Instagram Access Token
Log in to your Facebook Developers account.
Click on the App created for the Instagram Feed Account.
From the left sidebar, click on the Use Cases option.
Click the Customize button for the Manage messaging & content on Instagram option.
Expand the Generate access token section.
Click the Generate token option.
Log in to your Instagram account when asked.
Click the Allow button.
Check the I Understand checkbox.
Copy the new Access token.
Click the Done button.
Update the Access Token in the Instagram Feed Module
Open the page that contains the Instagram Feed Module.
Open the Instagram Feed module's settings.
In the Content tab → Account, click the Remove button.
Click the Add button.
Give the account a name. This can be anything you want.
Paste in the new Instagram Access token copied from the previous steps.
Click the Submit button.