VBA Form Locked for Input

Hello
I created this form in VBA and all of a sudden, it is now frozen, unable to input in the fields. It's as if another dialog box is open and preventing input in the form. Can someone help me, thanks!
Here are my captures:



----------Code below -------------

Private Sub Button4Fermer_Click()
Unload FormRegister
End Sub

Private Sub ButtonAjouter_Click()
'Double click on the add button

If ComboBox2.Value = " " Then
MsgBox "Please fill in the name and surname field"
Else
Dim ligne As Integer

If MsgBox("Do you confirm the addition of the data?", vbYesNo, "confirmation") = vbYes Then

Worksheets("Feuil2").Select

'number of the empty row in column A
ligne = Sheets("Feuil2").Range("A456541").End(xlUp).Row + 1

Cells(ligne, 1) = ComboBox_civilite.Value
Cells(ligne, 2) = ComboBox_nomprenom.Value
Cells(ligne, 3) = Txt_adresse.Value
Cells(ligne, 4) = Txt_codepostal.Value
Cells(ligne, 5) = Txt_ville.Value
Cells(ligne, 6) = Txt_telephone.Value
Cells(ligne, 7) = Txt_email.Value

Unload FormRegister

FormRegister.Show
Else
End If
End If
End Sub

Private Sub UserForm_Initialize()
ComboBox_civilite.AddItem "Mrs."
ComboBox_civilite.AddItem "Miss"
ComboBox_civilite.AddItem "Mr."
FormRegister.Height = 500
FormRegister.Width = 500

End Sub

Configuration: Windows / Chrome 96.0.4664.93