ActionMailer doesn't accepts content_type when the body of the message is from RTE

Hello I have a problem with the content type of ActionMailer. I am using markit-up and when I submit the form and send email with the entered message I get this in my box:
This is a message. I have this in my mailer:
mail(:content_type=>“text/html”,:to=>@email,:subject=>“Generated certificates”,:body=>issuer_mes.body)

where issuer_mes.body is the entered message. Can you help me? Thanks in advance :slight_smile: