The result of the additional field is not saved during registration. What could be the problem?

Question

DLE

Hello. Question for connoisseurs of DLE. In general, I created an additional field for the user - a phone number. I insert an additional field into the registration and nothing is saved. The database is also empty. It is saved either through editing the profile or through the admin panel (essentially the same thing).
When registering:

<input placeholder="Например: [phone]" type="text" name="xfield[phone]"  class="reg_tf" />

When editing your profile:

<input autocomplete="off" placeholder="Например: [phone]" type="text" name="xfield[phone]" value="[xfvalue_phone]" class="post_tf" />

In the admin:

<input type="text" name="xfield[phone]" id="xfield[phone]" value="">

Answer 1

I decided

td><span class="icon-tf icon-phone"></span><input placeholder="Например: [phone]" type="text" name="xfield[phone]" id="xfield[phone]" value="" class="reg_tf" /></td>