Hi
Have you tried mentioning the content type in the advanced section of HTTP connection? Please refer to our documentation here..>>
http://sqlyogkb.webyog.com/article/155-connecting-using-http-tunneling
It states that “With Apache and mod_security extension enabled in Apache configuration it may be necessary to use ‘urlencode’.” Please try and use “urlencode” HTTP content type and check if the problem still persists.
Regards