how to fix this problem when i click on address this massge appeare NullPointerException (ServerResource:56 < ...)

<?xml version='1.0' encoding='UTF-8'?>

<!DOCTYPE properties SYSTEM 'http://java.sun.com/dtd/properties.dtd'>

<properties>

    <entry key="config.default">./conf/default.xml</entry>

    <entry key='web.port'>80</entry>
    <entry key='geocoder.enable'>true</entry>
    <entry key='geocoder.type'>google</entry>
    <entry key='geocoder.processInvalidPositions'>false</entry>
    <entry key='geocoder.onRequest'>true</entry>
    <entry key='geocoder.ignorePositions'>true</entry>
    <entry key='database.driver'>com.mysql.jdbc.Driver</entry>
    <entry key='database.url'>jdbc:mysql://localhost/traccar?allowMultiQueries=true&amp;autoReconnect=true&amp;useUnicode=yes&amp;characterEncoding=UTF-8&amp;sessionVariables=sql_mode=''</entry>
    <entry key='database.user'>root</entry>
    <entry key='database.password'>root</entry>

    <entry key='server.timeout'>120</entry>

</properties>

You need to use other geocoder provider, or get a Google key.

i change to other geocoder provider but still cant see address

<?xml version='1.0' encoding='UTF-8'?>

<!DOCTYPE properties SYSTEM 'http://java.sun.com/dtd/properties.dtd'>

<properties>

    <!-- SERVER CONFIG -->

    <entry key='web.enable'>true</entry>
    <entry key='web.port'>8082</entry>
    <entry key='web.path'>./web</entry>
    <entry key='web.cacheControl'>max-age=3600,public</entry>

    <entry key='geocoder.enable'>true</entry>
    <entry key='geocoder.type'>nominatim</entry>
    <entry key='geocoder.url'>https://locationiq.org/v1/reverse.php</entry>
    <entry key='geocoder.key'>5d00e7465f6b64</entry>

    <entry key='logger.enable'>true</entry>
    <entry key='logger.level'>all</entry>
    <entry key='logger.file'>./logs/tracker-server.log</entry>

    <entry key='filter.enable'>true</entry>
    <entry key='filter.future'>3600</entry>

    <entry key='event.enable'>true</entry>
    <entry key='event.ignoreDuplicateAlerts'>true</entry>
    <entry key='processing.computedAttributes.enable'>true</entry>

    <entry key='media.path'>./media</entry>

    <entry key='server.statistics'>https://www.traccar.org/analytics/</entry>

    <entry key='commands.queueing'>true</entry>

    <!-- DATABASE CONFIG -->

    <entry key='database.ignoreUnknown'>true</entry>

    <entry key='database.generateQueries'>true</entry>

    <entry key='database.changelog'>./schema/changelog-master.xml</entry>

    <entry key='database.loginUser'>
        SELECT * FROM users
        WHERE email = :email OR login = :email
    </entry>

    <entry key='database.selectPositions'>
        SELECT * FROM positions WHERE deviceId = :deviceId AND fixTime BETWEEN :from AND :to ORDER BY fixTime
    </entry>

    <entry key='database.selectLatestPositions'>
        SELECT positions.* FROM positions INNER JOIN devices ON positions.id = devices.positionid;
    </entry>

    <entry key='database.updateLatestPosition'>
        UPDATE devices SET positionId = :id WHERE id = :deviceId

Have you restarted service after changing config?

i made stop service then restart but until now i didn't get address .