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Go to Graph API Tool: https://developers.facebook.com/tools/explorer
Set the Facebook App and ensure you choose a Page access token, select your required permissions shown in screenshot
Click the blue “i“ icon → Open in Access Token Tool
Notice the expiry date is only about 2 hours (short lived token). Press the “Extend Access Token“ button at the bottom of the page
Copy the new token, this one should not expire
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