Can't download ebooks from ios devices

[charlweed]

I have Calibre server 5.32 on Linux (Ubunbtu 20.4), iOS 15.1 and iPadOS 15.1.
I can download ebooks as expected from Windows 10, but not from Apple devices. Apple devices can "Read" books on the server as expected. I suspect this is a SSL/TLS issue that's only for "Download".

When I try to use Chrome or Firefox to download an epub or mobi formatted file, the browser displays an unhelpful "Download Failed" pop-up. When I try to use Safari, instead of a message pop-up, the page changes to the message:

Failed to load books from calibre library, with error:
Failed to communicate with "/interface-data/books-init?library_id=speculative_fiction&sort=timestamp.desc&1638471540815", network error. 
Is the server running and accessible?

When I examine the output from calibre-server I see many copies of :

Dec 02 11:02:45 executor calibre-server[280216]: Unhandled exception in state: State: do_ssl_handshake Client: 192.168.0.8:56012 Request: WebSocketConnection
Dec 02 11:02:45 executor calibre-server[280216]: Traceback (most recent call last):
Dec 02 11:02:45 executor calibre-server[280216]:   File "calibre/srv/loop.py", line 621, in tick
Dec 02 11:02:45 executor calibre-server[280216]:   File "calibre/srv/loop.py", line 215, in do_ssl_handshake
Dec 02 11:04:27 executor calibre-server[280216]: OSError: [Errno 0] Error

As far as I can tell, these errors are only printed when I click the "Download" button, NOT when I click the "Read" button.

Any help on this would be appreciated

[kovidgoyal]

Try it without ssl first.

[charlweed]

I disabled SSL, and found that downloads works as expected on iPadOS 15.1 :/

[kovidgoyal]

Hmm, well I dont have any insight to offer, according to those logs the device isnt doing the SSL handshake properly.