API Path Resolution Issue with Lambda Function

Progress So Far:

Critical Information Retrieved:

Obtained my root namespace ID: xxxxxxxx
Obtained my member ID: xxxxxxx
Added team_data.content.write and other team permissions to my app

Implementation:

Successfully modified my AWS Lambda function to include both the namespace ID and member ID
Implemented the correct headers as advised
Updated my access token after adding the new permissions
Simplified the target path to /output-eagle/{filename} to eliminate potential path complexity issues

Current Issue:
Despite implementing all the recommended changes, I'm still receiving a "409 Conflict" error with the message:
{"error_summary": "path/no_write_permission/...", "error": {".tag": "path", "reason": {".tag": "no_write_permission"}, "upload_session_id": "pid_upload_session:ABIJH3zrQHGELnZnhSrIXYOcu2U9_8zfcTi0nbk8vg-kKQkKnA"}}
Current API Request Details:
python# Headers being sent:
headers = {
'Authorization': f'Bearer {dropbox_token}',
'Content-Type': 'application/octet-stream',
'Dropbox-API-Select-User': 'xxxxxxx',
'Dropbox-API-Path-Root': json.dumps({
".tag": "namespace_id",
"namespace_id": "xxxxxxxxx"
}),
'Dropbox-API-Arg': json.dumps({
'path': '/output-eagle/filename.jpg',
'mode': 'add',
'autorename': True,
'mute': False
})
}

also tried:
headers = {
    'Authorization': f'Bearer {access_token}',
    'Dropbox-API-Select-User': member_id,
    'Dropbox-API-Path-Root': json.dumps({
        ".tag": "root",  # Changed from "namespace_id"
        "root": root_namespace_id
    }),
    # Other headers...
}

I've confirmed that:

My access token was refreshed after adding the permissions
I'm using the correct member ID and namespace ID
My app has the following permissions enabled:

team_data.member
team_data.team_space
team_data.content.write
files.team_metadata.write
files.team_metadata.read

What else should I check? Am I missing something in my implementation, or could there be a team-level permission issue that I need to address?