Error with downloading photo with Customm Apps module

Custom Apps
1

I am writing a custom module for uploading a file to the server using a previously obtained URL.
Here is the communication section:

{
    "url": "{{parameters.upload_url}}",              
    "method": "POST",                                
    "headers": {
        "Content-Type": "multipart/form-data"         
    },
    "qs": {
        "application_id": "{{connection.application_id}}",         
        "application_key": "{{connection.application_key}}",   
        "access_token": "{{connection.accessToken}}",          
        "session_secret_key": "{{connection.session_secret_key}}"
    },
    "body": {
        "Content-Type": "image/ipg",                 
        "pic1": "{{parameters.imageData}}"
    },
    "response": {
        "output": {
            "response": "{{body}}"
        },
        "valid": {
            "condition": "{{response.photos}}",           
            "message": "✅ Downloading successful. Photo: {{response.photos}}"
        },
        "error": {
            "message": "[{{statusCode}}] ❌ Error: {{body.error_msg}}"
        }
    },
    "log": {
        "sanitize": [
            "request.qs.access_token",              
            "request.qs.sig",                       
            "request.qs.session_secret_key"          
        ]
    }
}

The URL is correct. I uploaded via it using the HTTP module.
But when uploading through my module, the server gives the following error:

{
    "error_msg": "one.image.upload.client.ContentUploadServerException: CONNECTION_ERROR",
    "error_code": "1",
    "error_data": "CONNECTION_ERROR"
}

Where should I look? I can’t figure out how to find the cause.
Technical support is silent and doesn’t answer the question of what this error is.