I write these in problem.xml

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<problem>
    <names>
        <name language="english" main="true" value="LytchenLovesJSON"/>
    </names>
    <judging cpu-name="Intel(R) Core(TM) i3-8100 CPU @ 3.60GHz" cpu-speed="3600" input-file="" output-file="">
        <testset name="tests">
            <time-limit>1000</time-limit>
            <memory-limit>134217728</memory-limit>
            <test-count>12</test-count>
            <input-path-pattern>tests/%02d.in</input-path-pattern>
            <answer-path-pattern>tests/%02d.ans</answer-path-pattern>
            <tests>
                <test method="manual"/>
            </tests>
        </testset>
    </judging>
    <files>
        <resources>
            <file path="files/testlib.h" type="h.g++"/>
        </resources>
    </files>
    <assets>
        <checker type="testlib">
            <source path="files/check.cpp" type="cpp.g++"/>
            <copy path="check.cpp" type="cpp.g++"/>
        </checker>
    </assets>
    <properties>
        <property name="tests-wellformed" value="false"/>
    </properties>
</problem>

and in the folder tests there are 01.in, 01.ans, ..., 12.in, 12.ans

however, when I try to update contest, it says User {name='xzm2019'}: XML-descriptor of the problem 'C' has illegal format: The specified test count in testset 'tests' is 12, but actual number of tests is 1.

who can help me, what's wrong in these tests. thank you.