"Timed out" is returned when parsing certain URLs.

[YamatoRyou]

maubot version: 0.5.1
rss version: 0.4.1

maubot runs as a Docker container and has a proxy configured:

HTTPS_PROXY="http://192.168.0.1:8082"

But some URLs still cannot be connected through the instance and return "Connection timeout". There are two manifestations:
a) The URL is successfully added using the command and the feed title is returned, but "Connection timeout" is returned when getting the entry;

Failed to parse feed 10 / https://github.com/vector-im/element-web/releases.atom: Connection timeout to host https://github.com/vector-im/element-web/releases.atom

b) When adding the URL using the command, "Connection timeout" is returned, so it cannot be added.

However, the strange thing is that these URLs can be accessed normally in the container's Shell:

/opt/maubot # curl -I https://github.com/element-hq/element-web/releases.atom
HTTP/1.1 200 Connection established

HTTP/2 200 
content-type: application/atom+xml; charset=utf-8
content-length: 132595
vary: X-PJAX, X-PJAX-Container, Turbo-Visit, Turbo-Frame,Accept-Encoding, Accept, X-Requested-With
etag: W/"64867d9e3b87b7f331dc10699d5dee59"
cache-control: max-age=0, private, must-revalidate
strict-transport-security: max-age=31536000; includeSubdomains; preload
x-frame-options: deny
x-content-type-options: nosniff
x-xss-protection: 0
referrer-policy: no-referrer-when-downgrade
server: github.com
accept-ranges: bytes