Shortcodes in the text of a post or page are just text. This does not affect the ability to save the post/page.
Try creating a simple snippet(even an empty one) and inserting it into the page text. Will you be able to save the page?
Try replacing the fvplayer shortcode with the woody shortcode. Create a test snippet with simple output and paste it instead of fvplayer. If this works, it means that the problem is in the fvplayer shortcode
Hello.
Do you want to forward a snippet using a shortcode? If so, you will not succeed, since the header function must be called before any output to the browser.
Здравствуйте.
Нужно обновить плагин. Мы исправили эту проблему.
Вы можете зайти на сайт по ftp и удалить папку с плагином, тогда админка заработает. После этого установить плагин заново
You need to look at and compare the PageSpeed check results to understand why the slowdown is occurring. Can you send me the site address or screenshots of the checks?