Hi Everyone,

I am attempting to send templated email through SendMail method.
When i was testing individual mails for functionality it worked perfectly fine. Now that i have looped out multiple mails, and want to send from a list i am getting an error.

Here is the error in detail when i try to run the script:
Line: 57, Column: 1
System.EmailException: SendEmail failed. First exception on row 1; first error: INVALID_FIELD_WHEN_USING_TEMPLATE, When a template is specified the plain text body, html body, subject and charset may not be specified : []

Here is the script that i am trying to run:
 

// Promo/Contact Objects
        List<Promotion__c> PromoList = new List<Promotion__c>(); // list of promo/title
        List<Title_Contact__c> ContactList = new List<Title_Contact__c>(); // list of title/contact
        List<String> TitleList = new List<String> (); //list to use to bind title contacts and titles needed (used to manage record size out of Title_Contact__c)
        Map<String, String> MailingList = new Map <String, String> (); //List of Promo/Contact that need to be mailed
        // Mailer Objects
        OrgWideEmailAddress Orgid = [SELECT Id FROM OrgWideEmailAddress WHERE displayname = 'APub Promo Notify']; //select the correct send from address
        EmailTemplate template = [SELECT id FROM EmailTemplate WHERE developerName = 'Ebook_PBook_Deals']; //get the standard template to be used        
        Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage(); //initialize the individual emails
        List<Messaging.SingleEmailMessage> emails2send = new List<Messaging.SingleEmailMessage>(); //list of 'mail' to be sent through sendMail
        List<List<String>> MailList = new List<List<String>>();
        
        ///////////////////Create the MailingList MAP
        
        PromoList = [SELECT id, Title__r.id FROM Promotion__c  WHERE Notification_Status__c = 'Queued']; //;AND Start_Date__c = NEXT_N_DAYS:1
        if (!PromoList.isEmpty()){ //check if we have promos to act on
            for (Promotion__c title : PromoList) { //loop through to isolate the titles needed
                TitleList.add(title.Title__r.id); // build the list of titles in the title list string
            }
            System.debug('We have ' + PromoList.size()+' promotions to act on.');
            ContactList = [SELECT Legal_Name__r.Id, Title__r.Id 
                           FROM Title_Contact__c 
                           WHERE Title__r.Id IN :TitleList 
                           AND Role__c IN ('Author', 'Agent')]; //grab the recipients from the needed titles and the specific roles
            
            for (Title_Contact__c tc : ContactList) { //loop through lists to find matches on each level
                for (Promotion__c p : PromoList){
                    if(tc.Title__r.id == p.Title__r.id) { // have a match? add it to the map
                        MailingList.put(tc.Legal_Name__r.id, p.id);
                        
                    }              
                }
            }
            System.debug(MailingList);
        }else{
            System.debug('No Promotions to act on.');
            //No promotions in PromoList to send on.
        }
        
        
        ///////////////////Use the MailingList to create the individual email, and add to emails2send
        //If we have people to mail, compile mails, if not dont send
        if (!MailingList.isEmpty()){
            for (String c : MailingList.keySet()) {
                System.debug(c);
                System.debug(MailingList.get(c));
                String Contact = c;
                String Promotion = MailingList.get(c);
                mail.setOrgWideEmailAddressId(Orgid.id); //from address
                mail.setTemplateId(template.id); //standard template
                mail.setWhatId(Promotion); // what promo to merge
                mail.setTargetObjectId(Contact); // Specify who the email should be sent to.
                
                emails2send.add(mail);
            }
            Messaging.sendEmail(emails2send);
        }

The error is referencing fields that i am not attempting to alter in the building of "mail".
Thoughts?

Thanks in advance!