I recently had an issue where a WordPress website I was building could not connect to itself for wp-cron or background tasks.
This was the error:
curl: (35) error:1408F10B:SSL routines:ssl3_get_record:wrong version number
It turns out I had a faulty nginx configuation, and the server block was missing the
ssl directive. The certificates worked in both Chrome and Firefox without warnings, but they weren’t doing what the needed to for curl to work.
listen 443 ssl;
ssl to the listen line fixed the cURL error and wp-cron