Bad Request (#400) Unable to verify your data submission. in yii2 how to solve?

Question

Yii

Gentlemen, I have an error when submitting a form in yii2:

Bad Request (#400) Unable to verify your data submission.

I have <?= Html::csrfMetaTags() ?> in my template code. I create a form using ActiveForm
Here is the form code:

<?
                 $form2 = ActiveForm::begin(['id' => 'user-univer']);
                        echo $form2->field($model2, 'university')->label('Input university name:');
                        echo $form2->field($model2, 'degree')->label('Input your education specialization:');
                        //echo $form2->field($model2, 'date')->label('Input your education date:');
                        echo '<label class="control-label">Education time:</label><br/>';
                        echo '<span>Start date of your education:</span>';
                        echo DatePicker::widget([
                                'model' => $model2,
                            'attribute' => 'date_from',
                            'value'  => $value,
                            'dateFormat' => 'dd.MM.yyyy',
                        ]);
                        echo '<span>End date of your education:</span>';
                        echo DatePicker::widget([
                                'model' => $model2,
                                'attribute' => 'date_to',
                            'value'  => $value,
                            'dateFormat' => 'dd.MM.yyyy',    
                        ]);
                        echo '<br/><br/>';
                        
                        
                        echo $form2->field($model2, 'info')->textarea()->label('Any other information about your university degree:');
                        echo Html::submitButton('Add university', ['class' => 'btn btn-primary btn-univer']);
                        ActiveForm::end(['id' => 'user-univer']);
                        
                        } ?>

Initially, I thought that the problem was in the datepicker, but without it, everything is also ok. What could be the problem?

Answer 1

The problem I had was that in the view file it turned out that one form was inside another, which apparently caused problems with reading the token.

Answer 2

Why does Bad Request (#400) occur on a form in yii 2.0?