Setting cookies??

I’ve developed a shortcode that will log a user in (as “anonymous” subscriber) – it works great in most circumstances (all the time on my production server) – but on my sandbox server, it occasionally and seemingly randomly breaks with a “headers already sent” message, caused by a changing source.

is there any way to assure that a shortcode runs earlier in the page load process?

https://ww.wp.xz.cn/plugins/shortcodes-ui/