How can I validate the phone number? Is it validate using loop? And why it shows error for the [phone+esi].
And also how to validate the username if I want to make sure all the input is characters

INCLUDE Irvine32.inc

.data
    tryDigit BYTE 'Enter 10 digits here: ',0
    MAX = 10
    phone BYTE MAX+1 dup (?)
    yesDigit BYTE 'Digit',0
    notDigit BYTE 'Not Digit',0

.code
MAIN PROC
    
    mov edx,0
    mov eax,0
    mov edx, OFFSET tryDigit
    call WriteString
    mov edx, OFFSET phone
    mov ecx, MAX
    call ReadString
    call Crlf
    

;Validate phone number
L1:
    mov ecx, LENGTHOF phone
    mov esi, OFFSET phone
    mov al, [phone+esi]
    call IsDigit
    jnz errorMsg
    mov edx, OFFSET yesDigit
    call WriteString
    call Crlf
    inc esi
    Loop L1
    
errorMsg:
    mov edx, OFFSET notDigit
    call WriteString
    call Crlf
    
    exit

MAIN ENDP
END MAIN