getTests webservice returns empty response

[Amab]

The getTests service always returns an empty response.

The curse has got the tests data download option enabled:

getTestConfig call to check if there are tests available in the course:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:swad">
   <soapenv:Header/>
   <soapenv:Body>
      <urn:getTestConfig>
         <!--Optional:-->
         <wsKey>[REDACTED]</wsKey>
         <courseCode>4270</courseCode>
      </urn:getTestConfig>
   </soapenv:Body>
</soapenv:Envelope>

getTestConfig response showing test data is available:

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:swad="urn:swad" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <SOAP-ENV:Header />
   <SOAP-ENV:Body>
      <swad:getTestConfigOutput>
         <pluggable>1</pluggable>
         <numQuestions>55</numQuestions>
         <minQuestions>1</minQuestions>
         <defQuestions>4</defQuestions>
         <maxQuestions>20</maxQuestions>
         <feedback>fullFeedback</feedback>
         <visibility>31</visibility>
      </swad:getTestConfigOutput>
   </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

getTests call:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:urn="urn:swad">
   <soapenv:Header/>
   <soapenv:Body>
      <urn:getTests>
         <!--Optional:-->
         <wsKey>[REDACTED]</wsKey>
         <courseCode>4270</courseCode>
         <beginTime>0</beginTime>
      </urn:getTests>
   </soapenv:Body>
</soapenv:Envelope>

getTests response:

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:swad="urn:swad" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <SOAP-ENV:Header />
   <SOAP-ENV:Body>
      <swad:getTestsOutput>
         <tagsArray />
         <questionsArray />
         <answersArray />
         <questionTagsArray />
      </swad:getTestsOutput>
   </SOAP-ENV:Body>
</SOAP-ENV:Envelope>