Here is my program:

public class Outbound_Example_3 {
    public void invoke(){
        Messaging.SingleEmailMessage msg =new Messaging.SingleEmailMessage();
        Contact con=[select id ,AccountId from Contact where createdDate=TODAY];
        msg.setTargetObjectId(con.Id);
        msg.setWhatId(con.AccountId);
        EmailTemplate et =[select id from EmailTemplate where name='Case Response'];
        msg.setTemplateId(et.id);
        
        Document doc =[select id,Name,Body,ContentType ,Type from Document where name='Email Messaging'];
        Messaging.EmailFileAttachment eft1 =new Messaging.EmailFileAttachment();
        eft1.setFileName(doc.Name+doc.type);
        eft1.setBody(doc.body);
        eft1.setContentType(doc.ContentType);
        
        PageReference p=Page.EmailSerc;
        Blob body=p.getContentAsPDF();
        Messaging.EmailFileAttachment eft2 =new Messaging.EmailFileAttachment();
        eft2.setFileName('EmailSerc');
        eft2.setBody(body);
        List<Messaging.EmailFileAttachment> files =new List<Messaging.EmailFileAttachment>{eft1,eft2};
        msg.setFileAttachments(files);
        Messaging.Email[] emails =new Messaging.Email[]{msg};
        Messaging.sendEmail(emails);    
        
    }
}


Outbound_Example_3 ou=new Outbound_Example_3();
ou.invoke();


Please let me know where am I going wrong.
Thanks!