What causes to server to say the packet is malformed?
If the RADIUS server is compliant with the basic packet construction the AXL RADIUS Client will construct correct packets. However it’s possible to create attributes with a tag value of 0 or with an empty data value. Both of these conditions are forbidden by servers. There is no such attribute tag as 0 (valid values are 1 to 255). Attributes must always have data with a length greater than 1 byte. Attribute values with no value must not be sent.