@steve02081504 For now, the mechanism is to send the cache file updated date with if-modified-since header, and if 302 Not Modified is returned, the entire data of the file is not transferred.
We need to rewrite the code to check the file hash first and skipping entire communication process, so please wait a bit.

@steve02081504 Does it happen even if you rewrite the homeurl from http to https?

@steve02081504 A 502 Bad Gateway error is returned because an error occurred at one of the relay servers leading up to the nanachi.sakura.ne.jp server.
It may be a problem in your environment, or it may be a technical problem on the Sakura Internet side. At least on the SSP side, the only thing I can do is to increase the number of retries.

@steve02081504 There is a log that succeeds with HTTP code 304, so it is not an update cache issue.
Since it is stopping with a 502 error, it is probably an error on the server side or some cache server leading up to it.

@steve02081504 Please check network log. (not update log)