Hello all,

I'm developping a batch which send emails to a contact List but it doesn't work and I'm getting all time this error :
[code]
INVALID_FIELD_WHEN_USING_TEMPLATE, When a template is specified the plain text body, html body, subject and charset may not be specified : []
[/code]

And below, my code :
[code]
List<EmailTemplate> emailTemplateList = [
      SELECT Id
      FROM EmailTemplate
      WHERE DeveloperName = :emailTemplateName
];

List<Messaging.SingleEmailMessage> emailsToSend = new List<Messaging.SingleEmailMessage>();

for(Contact aContact : contactList){
                        
      Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
                            
      mail.setTargetObjectId(aContact.Id);
                        
      mail.setOrgWideEmailAddressId(oweaMap.get(emailMap.get(aRegion)).Id);
                    
      mail.setSubject(mailSubject);
                        
      mail.setSaveAsActivity(false);
                        
      mail.setBccSender(false);
                        
      mail.setUseSignature(false);
                        
      mail.setCharset('UTF-8');
                                                
      mail.setTemplateId(emailTemplateList[0].Id);
                        
      emailsToSend.add(mail);
}

Messaging.sendEmail(emailsToSend);
[/code]

The error is on the last line : Messaging.sendEmail(emailsToSend);

I've trying in selecting Body, HtmlValue and Subject field on the EmailTemplate object but it doesn't work..

What's wrong please?