Success message doesn’t display

I have 2 Contact Form 7 on my website. one of them works properly. It displays successful submit message and resets the input fields.

Another form in the attached page also sends mail successfully but it doesn’t display successful message, it doesn’t reset the input fields either.

Both WordPress and Contact Form 7 is the in the latest version.

Here is the code block of Form Tab:

<label> Name
    [text your-name autocomplete:name] </label>

<label> E-mail
    [email your-email autocomplete:email] </label>

<label> Phone number 
    [tel tel] </label>

<label> Width 
    [number width min:0 max:10000] </label>  

<label> Depth
    [number depth min:0 max:10000] </label>

<label> Leg Model 
    [select* LegModel "Golden X Leg" "X Leg" "U Leg" "Golden U Leg" "Another Leg"] </label>

[submit "Submit"]

The page I need help with: [log in to see the link]