Mike,

File is recognized as PDF but content of it is corrupted. When I try to open the file it says FAIL TO LOAD PDF DOCUMENT.

here is the code

global with sharing class scheduledinvoices implements Schedulable{
global ApexPages.StandardController controller;
global Invoice__c[] inv { get; set;}

global PageReference pdf { get; set;}

global void execute(SchedulableContext SC) {

inv=[select id, name, Email__c from WPOSP__Invoice__c where 
                             Set_recurring_payments__c=true];

for(Invoice__c si: inv){

pdf = Page.Recurring_Invoice;
    // add parent id to the parameters for standardcontroller
    pdf.getParameters().put('id',(String)si.id);


    // the contents of the attachment from the pdf// returns the output of the page as a PDF

    Blob b= pdf.getContent();
     
     
    Messaging.EmailFileAttachment attach = new Messaging.EmailFileAttachment();
   
    attach.setFileName(si.name+'.pdf');
  
    attach.setBody(b);
 string[] toaddress = si.WPOSP__Email__c.split(',', 0);
 

    Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
    mail.setUseSignature(false);
    mail.setToAddresses( toaddress );
    mail.setSubject('Your Statement');
    mail.setHtmlBody('Dear Customer,<br><br> Please find your statement attached in the email.');
    mail.setFileAttachments(new Messaging.EmailFileAttachment[] { attach }); 
 
    // Send the email
    Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
   
}
}
}