The issue is being caused by the encryption that Instagram/Facebook requires in regards to access tokens. This encryption relies on the Salt hashes in the wp-config.php file. To add these hashes to your config file, follow the step below.
1- Access your wp-config.php in your FTP server; if you need more information on finding and editing this file, please check this guide: How to Edit wp-config.php File in WordPress (wpbeginner.com).
2- Locate the Authentication Keys and Salts section that should look like so:
If you are using the Instagram feed plugin:
Add and define the following hashes SBI_ENCRYPTION_KEY and SBI_ENCRYPTION_SALT. You would use the same format as the LOGGED_IN_SALT and LOGGED_IN_KEY in that file, but ensure that the value of the new Key and Salt are new and unique.
If you are using the Facebook feed plugin:
Add and define the following hashes CFF_ENCRYPTION_KEY and CFF_ENCRYPTION_SALT. You would use the same format as the LOGGED_IN_SALT and LOGGED_IN_KEYin that file, but ensure that the value of the new Key and Salt are new and unique.
If you do not have WordPress security keys or are not sure how to make a new unique salt or key, you can generate them here from the official WordPress salt generator. Load the page and copy a value from any of the fields to use as your unique Salt or Key for our plugin to use. The result should look similar to the example below.
Note: This example only shows the correct syntax; the values will be different on your site. Do not use any of these values on your site.
define('LOGGED_IN_KEY', '|j^Y+yDnc8P.*(X;K=bWUrL9<JU!|qPm`U*I-bwRdjub*ZNe{@m}`|/Beq%$n]J|');
define('LOGGED_IN_SALT', 'Cvy?[V4mNd!VV4-{N !_{4P/z*wfDr8G)Z-<V-*v|R$}MY-vC{B4G&x1mU%O7,nv');
define('CFF_ENCRYPTION_KEY', '|j^Y+yDnc8P.*(X;K=bWUrL9<JU!|qPm`U*I-bwRdjub*ZNe{@m}`|/Beq%$n]J|');
define('CFF_ENCRYPTION_SALT', 'Cvy?[V4mNd!VV4-{N !_{4P/z*wfDr8G)Z-<V-*v|R$}MY-vC{B4G&x1mU%O7,nv');
The important part is to make sure the values for the two SBI or CFF items above matches on both the local and production site if you use separate ones, this way you can move your site from one location to the other without having to reconnect the sources in our plugins.
Once they are set, do not change them. After that, you have to reconnect the Instagram or Facebook sources to the plugin.
