How to slove critical alert

Force Restart your phone. It may take a couple of attempts to get the speed and sequence of the key presses correct. The las step of holding the side button until the Apple logo appears could take up to 15 seconds. Ignore any thing else you see on the screen until the Apple Logo appears.

Force restart iPhone - Apple Support

You need to have patience when you ask a question here. We are all just fellow users - no one from Apple participates in these forums - and this is not live chat, so it will usually take longer than one or two minutes, which is all you waited before reposting, before someone even sees your question, much less has a chance to reply. And demanding a reply is rude, though you may not have meant it so.

Regards.