Your test script is incorrect, replace msg.setHtmlText() in your test script with lines below and try again:

   var contents = "";
   contents += "<a href='www.yahoo.com'>Yahoo link</a>";
   contents += "<br>";
   contents += "And, this is a <b>bold text</b>";
   email.setHtmlText(contents);

In your test script, the closing tag for <b>, should be </b> but not <b/>.

works with the below code 

   var MQ= aqua.mail.newMailQueue()
   var msg = aqua.mail.newMessage();
   msg.addTo("tariqrahiman@aquafold.com");
   msg.addCC("tariqrahiman@hotmail.com");
   msg.addBCC("tariqrahiman@gmail.com");
   msg.setFrom("tariqrahiman@aquafold.com");
   msg.setSubject(" TEST - Report");

   var contents = "";
   contents += "<a href='www.yahoo.com'>Yahoo link</a>";
   contents += "<br>";
   contents += "And, this is a <b>bold text</b>";
   msg.setHtmlText(contents);
   msg.setText("Excel Report Message");
   MQ.sendMail(msg);