Magento 2 Custom cron not working

Question

I am trying to run custom cron but, I got below error in system.log while execute cron:run command.

main.WARNING: Could not acquire lock for cron group: default, skipping run [] []

crontab.xml file

<group id="default">
        <job name="test_cron" instance="Vendor\Module\Cron\Test" method="execute">
            <schedule>* * * * *</schedule>
        </job>
</group>

Cron/Test.php

namespace Vendor\Module\Cron;

class Test {

    public function execute() {

        $writer = new \Zend\Log\Writer\Stream(BP . '/var/log/customcron.log');
        $logger = new \Zend\Log\Logger();
        $logger->addWriter($writer);
        $logger->info("cron works");
   }
}

Answer 1

crontab.xml file

  <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Cron:etc/crontab.xsd">
        <group id="default">
            <job name="test_cron" instance="Vendor\Module\Cron\Test" method="execute">
                <schedule>*/15 * * * *</schedule>
            </job>            
        </group>
    </config>

Cron/Test.php

namespace  Vendor\Module\Cron;

class Test
{
    public function execute()
    {
       $writer = new \Zend\Log\Writer\Stream(BP . '/var/log/customcron.log');
        $logger = new \Zend\Log\Logger();
        $logger->addWriter($writer);
        $logger->info("cron works");
        return $this;
    }
}

I think your code is almost right. Please recheck your code and then flush cache.

php bin/magento cache:flush

Run the indexing cron job

bin/magento cron:run --group index

Run the default cron job

bin/magento cron:run --group default

check link https://devdocs.magento.com/guides/v2.3/config-guide/cli/config-cli-subcommands-cron.html

If it's not work please check your table "cron_schedule"

 SELECT * FROM cron_schedule where job_code='test_cron';

If you found any records? then delete that records and run all commands again.