I'm having problems with my Face ID

Have a look at these two articles -

If an alert says Face ID has been disabled on your iPhone or iPad Pro

If an alert says Face ID has been disabled on your iPhone or iPad Pro - Apple Support

If Face ID isn't working on your iPhone.

If Face ID isn't working on your iPhone or iPad Pro - Apple Support (AZ)

rachakorn162 Said:

"What should i do?: A problem was detected…"

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What to Do:

Provide a Screenshot:

You should provide a screenshot of the error message, and inform us of what occurred, so that it can be easily troubleshot in these forums: Take a screenshot on your iPhone - Apple Support