Publishing a post to a Page, via the API that contains a link or an image returns the following error response "{ code: 1, message: 'An unknown error occurred' }" The posts are successfully published though.
Unfortunately Facebook has disabled the bug report functionality so I guess we just have to scream into the void until it fixes itself.

When trying to publish a post containing link information in the message, the post is successfully published, but the API returns an error response.
As a result, the user cannot confirm the error details and cannot determine whether the post was successfully published or not.
Expected Behavior: If the post is successfully published, I expect a success response instead of an error response.
API Endpoint
POST /{page-id}/feed
Reference: https://developers.facebook.com/docs/graph-api/reference/v21.0/page/feed#publish
Request Sample
{
"message": "message https://www.example.com",
"link": "https://www.example.com",
"child_attachments": [
{
"link": "https://www.example.com",
"name": "Link title",
"picture": "https://s3-ap-northeast-1.amazonaws.com/post-image/a0e0b694-35db-4225-89ab-6d21e89e3ad8.jpeg",
"description": "Link description",
"call_to_action": {
"type": "NO_BUTTON"
}
}
],
"multi_share_end_card": false
}
Response Sample
"error": {
"code": 1,
"message": "An unknown error occurred"
}

I am currently creating an application which uploads information to Facebook using the Facebook Graph API. However, I am currently facing an error when trying to initialize an upload session.

When I write the following C-URL:

curl -X POST "https://graph.facebook.com/v21.0/<THE PAGE ID>/video_reels" \     -H "Content-Type: application/json" \     -d '{{            "upload_phase:"start",            "access_token":"<THE ACCESS TOKEN>"         }}' 

I get the error:

{"error":{"message":"Unsupported post request. Object with ID <PAGE ID> does not exist, cannot be loaded due to missing permissions, or does not support this operation. Please read the Graph API documentation at https:\\/\\/developers.facebook.com\\/docs\\/graph-api","type":"GraphMethodException","code":100,"error_subcode":33,"fbtrace_id":"ARVFrHVkhXZTsIN4Lzal-Gb"}} 

I have tried to change the permissions on the Facebook account, but when I refresh the page, nothing has changed. Has anybody got an idea what the problem could be?

Facebook says a page long lived access token will never expired but somehow mine got expired today after 60 days. The error message says: Error validating access token: Session has expired ....
If the token does expire, is there a way to repeatedly refresh the page token after a certain period?

i am trying to add a business manager to the partner account for another business page via facebook api, i have tried several apis, but failed. I want to grant access to facebook page.

Below are some of the apis i used in postman:

https://graph.facebook.com/v17.0/page-id/assigned_users?user=TO_WHOM_PERMISSION__WILL_BE_GRANTED&business=PAGE_BUSINESS_ID&access_token=TOKEN_OF_PAGE_OWNER&tasks[]=MANAGE https://graph.facebook.com/v17.0/BUSINESS_MANAGER_ID/owned_pages https://graph.facebook.com/v21.0/BUSINESS_MANAGER_ID/managed_businesses?existing_client_business_id=BUSINESS_ID&access_token=TOKEN_OF_OWNER 

But nothing worked, My main motive is to give access of facebook page to some other business manager by adding him to partner account, Do anyone have any idea how it can be done via api, any small help will be really appreciated, thanks in advance !!!