Symptoms
Prior to PBA upgrade to version 5.5 it was possible to use the SendSubscriptionNotificationForUser_API PBA API request with empty UserID like in the example below:
<?xml version="1.0"?>
<methodCall>
<methodName>Execute</methodName>
<params>
<param>
<value>
<struct>
<member>
<name>Server</name>
<value>MESSAGE</value>
</member>
<member>
<name>Method</name>
<value>SendSubscriptionNotificationForUser_API</value>
</member>
<member>
<name>Params</name>
<value>
<array>
<data>
<value><string>Welcome e-mail - Shared Hosting</string></value>
<value><i4>1002324</i4></value>
<value><i4></i4></value> <=== UserId is empty
</data>
</array>
</value>
</member>
</struct>
</value>
</param>
</params>
</methodCall>
After upgrade to PBA 5.5 API call fails if no UserID is specified with the following diagnostics:
<?xml version="1.0" encoding="UTF-8"?>
<methodResponse><fault><value><struct><member><name>faultCode</name><value><i4>-32600</i4></value></member><member><name>faultString</name><value><string>Server error. XML-RPC violation: /methodCall/params/param/value/struct/member/value/array/data/value[1]/i4</string></value></member></struct></value></fault></methodResponse>
Cause
UserID is mandatory parameter in the SendSubscriptionNotificationForUser_API method. It was incorrect that UserID was not required in PBA 5.4, and this behavior was corrected in PBA 5.5.
Resolution
Fill UserID in the API request with the ID of the user to send notification to.
If you use an external application to use the SendSubscriptionNotificationForUser_API API requests, that has no information of the actual UserID, then put 0 as the UserID parameter. In this case notification will be sent to the billing contact of a customer account.