The problem has already existed for more than half a year. This also affects the server version updater built into Nextcloud. The CLI tool for the update is often running into a timeout.
Error Messages:
Updater run in non-interactive mode.
Start update
Info: Pressing Ctrl-C will finish the currently running step and then stops the updater.
[✔] Check for expected files
[✔] Check for write permissions
[✔] Create backup
[✘] Downloading failed
Curl error: Failed to connect to download.nextcloud.com port 443: Connection timed out
Updater run in non-interactive mode.
Start update
Info: Pressing Ctrl-C will finish the currently running step and then stops the updater.
[✔] Check for expected files
[✔] Check for write permissions
[✔] Create backup
[✘] Downloading failed
Could not do request to updater server: Unknown SSL protocol error in connection to updates.nextcloud.com:443
Update failed. To resume or retry just execute the updater again.
See also:
My screenshots are a little older. But yes, the problem still exists. download.nextcloud.com has sometimes a really bad response time and is often down.