Wordpress REST API fails with Python - wordpress

Question

I've written a simple Python script to upload an image to a WP site:
import requests
import base64
BASE_URL = "https://example.com/wp-json/wp/v2"
media = {
"file": open("image.png", "rb"),
"caption": "a media file",
"description": "some media file"
}
creds = "wp_admin_user" + ":" + "app password"
token = base64.b64encode(creds.encode())
header = {
"User-Agent": "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36",
"Authorization":"Basic " + token.decode("utf-8")
}
r = requests.post(BASE_URL + "/media", headers=header, files=media)
print(r)
When using Python 3.9 on Windows, everything works as expected: I get a <Response [201]> reply and I can see the image in my site's media library.
When running the exact same script on a Linux, it fails with a 503 reply from the WP server:
<Response [503]>
The Linux is running Python 3.9.1
I can run the script again on Windows ten times, and it always works. I've searched the internets for the error and it's usually a WP configuration error, which doesn't seem to be the case here as the script works on Windows.
Any help is much appreciated!
I think that the problem is in the ip of the server where it hangs Linux