unRAID update 6.3.5 download hangs

I am attempting to update unRAID from 6.3.4 to 6.3.5 via the "Plugins" page. It seems to hang while trying to download the md5 hash file. This also happened when I updated from 6.3.2 to 6.3.4, so I just updated manually with no issues.

The system log isn't very helpful:

May 28 15:25:47 apollo emhttp: cmd: /usr/local/emhttp/plugins/dynamix.plugin.manager/scripts/plugin update unRAIDServer.plg
May 28 15:25:47 apollo root: plugin: creating: /tmp/unRAIDServer.sh - from INLINE content
May 28 15:25:47 apollo root: plugin: running: /tmp/unRAIDServer.sh
May 28 15:25:47 apollo root: plugin: creating: /tmp/unRAIDServer.zip - downloading from URL https://s3.amazonaws.com/dnld.lime-technology.com/stable/unRAIDServer-6.3.5-x86_64.zip
May 28 15:25:55 apollo root: plugin: creating: /tmp/unRAIDServer.md5 - downloading from URL https://s3.amazonaws.com/dnld.lime-technology.com/stable/unRAIDServer-6.3.5-x86_64.md5
May 28 15:40:22 apollo ntpd[16178]: ntpd exiting on signal 1 (Hangup)

I can download and update plugins and dockers without any issues. This has got me stumped. Has anyone seen this before or have any idea what is going on?

Thanks.