Anki is failing to sync in version 2.1.61 and 2.1.62 when using a custom sync server via a reverse proxy (Nginx with HTTPS). It works correctly on 2.1.60.
This is the error message it prints:
“A network error occurred.
Error details: error sending request for url (): connection error: unexpected end of file”
It is however syncing properly with 2.1.62 when connecting directly (without the reverse proxy). I am using the sync-server provided by Anki itself.