@Nam Ly The above code seems to be keeping the connection open until the processing is done for all the images on the client side. Could you try to close the connection after the response from the API i.e after data = response.read().decode(encoding) ?

I think since the connection is open until all your images or items are processed on client side in the for loop the API is closing the connection after the default limit.
The initial response object should contain all the image details from the API, could you consider to print this response and check if the later processing is the issue?

Increasing the time out on your http.client call is an option but that can still keep the connection open for a long time until all images in the response object are processed.

I added conn.close after data = response.read().decode(encoding) . It is the later processing that is the issue.

I did a google search regarding urlretrieve() and [Errno 10054] An existing connection was forcibly closed by the remote host . There is a solution that add edthe proxy to urllib.request. That seems to work for now. I do not know why this is the case though.

Thanks for the updates. The solution for proxy in the SO threads seem to be around setting up their proxy server because the corp network used by user needed one. If you are using a proxy network then you can also set one instead of localhost.

For the new error though, i think it would be easier to debug by printing the URL being called to check if the cleanup of URL retrieve is working as expected or you could try using urllib.request.urlcleanup() to ensure there is no stale data between calls for different images.