I can confirm this. If you go to Settings → Advanced → Relays, open the relay for editing, and select “Accept invalid certificates” in the Certificate Checks section, the connection is established. So it’s likely that they blocked something during the certificate verification process.
can confirm too that this workaround works.
it would be good to avoid the need to adjust settings
The solution of selecting “accept invalid certificates” doesn’t seem to work for me. The server just gets stuck on authentication and that’s it. Am I doing something wrong? My deltachat server is located in Russia with a Russian provider. I wonder, if it is strictly a TLS issue, will hosting a server without certificates solve the problem? It does make it less secure, I guess, but the official documentation says that deltachat’s internal encryption should suffice.
I am going to check if it’ll work that way whenever I get free time but it would be really good if the problem could be fixed somehow. Although, at the same time, I doubt that people developing this application have enough time to go head to head with an inane government ._.
It is with great regret that I confirm: custom relays have stopped working in Russia. Disabling certificate verification often helps, though not always.
I think the tracking and blocking occurs because I use mail.ru and Yandex mail in the deltachat app. Their servers track which clients are used and then block them, possibly based on these fingerprints.