Errors

Two kinds of failure, two behaviors.

Drops: retried

Network failures, server resets, TLS timeouts: the session dies, the player backs off (1 s doubling to 30 s) and reconnects. Nothing raises; log and on_connection narrate.

Broken sources: fatal

A bad container, a truncated file, a codec Telegram does not accept; retrying cannot help. The player stops, and player.error carries the reason:

player = tgrtmp.publish("broken.mp4", url, key)

while not player.stopped:
    time.sleep(0.5)

if player.error:
    print("failed:", player.error)

In the blocking API the same condition raises SourceError.

Warnings: not errors

player.warnings collects things the server will tolerate but you should fix: non-16:9 sources that Telegram will stretch, odd audio sample rates. They never stop the session.

Client vs player

Client.error (low level) explains why one connection closed. Player.error is the session-level verdict, set only when the player gave up for good.