I am working in Visual studio code. On the click of a lightning:button, I am calling a javascript method, inside the method I am calling a visual force page using window.open(url), submiting the form in visual force page, I am calling the apex class method to send an email. I got the message as 'Email Sent !!!,  but the mail was not received.

portion of JS

 openMail(event) {
 window.open('/apex/TestMail', 'Popup','height=500,width=600,left=100,top=100,resizable=no,scrollbars=yes,toolbar=no,status=no');
  
}
VF Page
TestMail

<apex:page controller="singleEmailExample">
 <apex:form >
Email Address : <apex:inputText value="{!toAddress}" />
 <apex:commandButton value="SendEmail" action="{!sendingEmail}"/> <br/>
  Email Status :<b> {!message}  </b>
 </apex:form>
</apex:page>

apex class

public with sharing class singleEmailExample {
    public string toAddress{get;set;}
    public string message{get;set;}
    public PageReference sendingEmail(){
        Messaging.SingleEmailMessage semail = new Messaging.SingleEmailMessage();
        String[] sendingTo = new String[]{toAddress};
        semail.setToAddresses(sendingTo);
        //String[] sendingToBccAdd = new String[]{‘XXXX@gmail.com’};
       // semail.setBccAddresses(sendingToBccAdd);
       // String[] sendingTocAdd = new String[]{‘XXXXX@gmail.com’};
      // semail.setCcAddresses(sendingTocAdd); */
        semail.setSubject('Single Email message Example');
        semail.setPlainTextBody('Hello!!!!!This is a test email to test single email message program');
        Messaging.sendEmail(new Messaging.SingleEmailMessage[] {semail});
        message='Email Sent !!!';
        return null;
    }
}

Please help me , I tried a lot, and got disappointed