when using the grid system in bootstarp column not coming in same row code example

Example 1: bootstrap grid

<div class="container">
  <div class="row">
    <div class="col-sm">
      One of three columns
    </div>
    <div class="col-sm">
      One of three columns
    </div>
    <div class="col-sm">
      One of three columns
    </div>
  </div>
</div>

Example 2: whatever by Clever Crane on May 31 2020 Donate Comment

<div class="col-lg-3 mb-4">