For most users, Face ID works fine, but there are exceptions. Some technology with a sufficient number of problems arise.
If you enter the number of users, there are two ways to solve the problem. Face ID to help adjust herself or completely restoring the default settings. Below is how it is done.
How to improve Face ID
Face ID System is designed so that it can re-learn after every failure. When the Face ID does not recognize your face the next time, simply enter your password immediately. This will convince the system that you – the owner of the phone, just look at this time a little bit different, or are in a different place. Ideally, when you enter a password Face ID will take details of your face and integrates them into a saved model.
Here is a quote from the document on the protection of Face ID:
If the Face ID you do not know, but the similarity is high, and immediately you type the correct password, the system will again scan your face and create a new, slightly modified, a mathematical model of the face.
How to reset Face ID
If Face ID appears too much trouble, you can configure the function anew. First, you need to reset all of its settings. This will remove the saved face model and all other information Face ID.
Step 1: Go to Settings -> Face ID and passcode -> Reset Face ID .
Step 2: You will see the same screen where you set up Face ID the first time. At this time, try to spend setting with good lighting.
Step 3: Click Start and move your head around. Try as much as possible pull the neck and face scanned from all angles. The second time, moved his head slowly.
When the Face ID will be set again, wait a couple of hours, until she remembers you again and get used to the surroundings