Xampp 1.7.1
Mercury 4.6.2

When you use the CodeIgniter mail class againts Mercury Mail using SMTP the following error is sent:

“554 Invalid HELO format”

To avoid this error, change your C:\xampp\MercuryMail\transflt.mer this way:

1) Comment line
#H, “[EHeh][EHeh]LO +[0-9]+.[0-9]+.[0-9]+.[0-9]*”, R, “554 Invalid HELO format”

2) Set this other line
H, “[EHeh][EHeh]LO +[0-9]+.[0-9]+.[0-9]+.[0-9]+.*”, X, “”

More doc http://community.pmail.com/forums/thread/4136.aspx

Best regards

Iñigo