Incorrect Email(without html) is sending through Mailgun

Question

I am using Mailgun API based extension in Expression engine CMS When i disable the Mail-gun its sending perfect html mail but when I enable Mailgun its sending Email like in this manner:

This is a multi-part message in MIME format.
Your email application may not support this format.

--B_ALT_565e9f7740811
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit

HELLO this is a message


--B_ALT_565e9f7740811
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable

<b>HELLO</b> this is a message

--B_ALT_565e9f7740811--

I type only once "HELLO this is a message" in this manner:

<b>HELLO</b> this is a message 

But its showing two times in the email please resolve this issue.

Answer 1

I had so much headache with sending though an API I ended up buying Escort ( https://devot-ee.com/add-ons/escort ) and it simply worked perfectly and saved a lot of time making it worth it. I use it with Mandrill, but it supports yours.

Hope this kind of answer is allowed, as I know it isn't directly solving your problem.