I may have found the reason why media traffic is blocked on Android.
I collected a traffic dump on port 587 and found a packet containing the WhatsApp CDN server address.
On Android, data is transferred via http/1.1, and the WhatsApp server address is visible in it. This packet is followed by multiple retransmissions, indicating that the traffic was blocked by TSPU (DPI).
On iOS, data is transferred via http/2, and the server address is encrypted in the packet. And the traffic successfully passes through to the proxy.
Originally posted by @ion-lane in #442
Originally posted by @ion-lane in #442