TextMesh Pro TMP_InputField ActivateInputField is not working in OnEnable

I am trying to select a Selectable (in this context it is a TMP_InputField ) in the script as follows:

Code (CSharp):

1.  
2. // Current interactable and focused component (Assigned from Inspector)
3. private Selectable currentSelectable;
4.  
5. private void OnEnable(){
6.   // Selecting the assigned selectable
7.   currentSelectable.Select();
8.   currentSelectable.OnSelect(null);
9. }

Inside OnSelect(...) of TMP_InputField, I have provided a way to change colours so that it appears as selected, as shown in snippet below:

Code (CSharp):

1. // Called when email input is selected
2. public void SelectEmailGroup(){
3.   Colors.SetColor(emailGroup, "blue");
4.   Colors.SetColor(passwordGroup, "gray");
5.   email.ActivateInputField(); // This line has no effect on the email Input Field
6. }

The above method SelectEmailGroup() is assigned to OnSelect(string) method of TMP_InputField via Inspector

Even though the colours are updated on the TMP_InputField, still I am unable to get the focus on it to enter via keyboard. I have to press <kbd>ENTER</kbd> key before doing so.

Kindly suggest some direction on the topic.