When i checked the iframe of working and non working ticket email, i found that,Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, webmaster@dummy-host.example.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
The iframe src is : http://localhost/otrs/index.pl?Action=A ... 5;FileID=2
and it gives internal server error..
But to my surprise, if i change the last param manually to FileID=1,
i.e. http://localhost/otrs/index.pl?Action=A ... 5;FileID=1
then the email works!!
What could be the problem? Please help.