I am trying to partially automate logging into the following site with VBA HTML, but facing a problem I have never experienced before.

In Step 1, my code is opening the web page and entering my card number. In Step 2, I am supposed to manually enter the password and manually click the 'Sign In' button.

Even with the correct password, the website is giving me an error saying I might have entered an incorrect card number or password. Both the card number and password stars are still showing in the text boxes.

Now, if I just copy the card number from the text box and paste it back, and then click the Sign In button again, I am able to log in. I am not sure why this is happening.

How is the web page able to determine if the card number was entered by the VBA code vs. manually?