easy-app | Structure for large and small applications | SDK library

I cloned this repo and installed everything required. The program is to apply for jobs in linkedIn. Everything works perfectly until its time to apply for the job. Then I get the error which is in pyautogui functions, which I am not allowed to change. The error is:

File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\site-packages\pyautogui__init__.py", line 691, in _normalizeXYArgs

return Point(int(firstArg), int(secondArg)) # firstArg and secondArg are just x and y number values

TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'

You can check the code by installing pyautogui.

Full stacktrace

This is my website URL http://saloon.ekvitech.com/schedule-appointment/ on this page I am using a 'easy-appointment-plugin' of WordPress to book an appointment. Here when you fill the appointment form step by step then you are towards to personal information form. When you fill this then the form is submitted for review by admin. But the problem is in that form there is a phone field and that field was accepting alphabet as well as digits. This should be not done with the phone as we know that phone number will accept only digits.

So I need to validate this field with digits only. If someone enters alphabets then error message arrises digits only.

I applying my code in the "header.php" file, I am stuck with my script code because the fields are autogenerated by WordPress plugin and all fields have same class how we can achieve this and validate should be done on single filed i.e. on phone field only.