This is infrastructure related, so not sure if this is the right place. But here goes anyway.

The feedback_plugin infrastructure seems to have been unavailable for a while. I can reach the mariadb.org frontend, but any calls from the plugin fails, and so does web browsers when trying to browse the statistics, for example https://mariadb.org/feedback_plugin/stats/server_count_by_month/

They seem to fail with: 504 - Service currently unavailable
After a minute or so.

2019-03-19 13:09:15 0 [Note] feedback plugin: report to 'https://mariadb.org/feedback_plugin/post' was sent

2019-03-19 13:10:15 0 [ERROR] feedback plugin: failed to read server reply

One effect of this is shutdowns blocking for a minute if the feedback plugin is enabled.