Download - NaN result

[fachamix]

I am getting the following error after execution of Download test...

[Download] Restarting measures with 10.000 MB of data...
[Download] The minimum delay of 8.000 seconds has not been reached
[Download] Restarting measures with 10.000 MB of data...
[Download] undefined
[Download] Final average speed: NaN MBps
[Download] Finished measures

Server = APACHE
SETTINGS=
{
latency: {
// Where is located your network.php file.
endpoint: './network.php',
// How many measures should be returned.
measures: 5,
// How much attempts to get a valid value should be done for each measure.
attempts: 3
},

upload: {
    // Where is located your `network.php` file.
    endpoint: './network.php',
    // The delay while you want to take measures.
    delay: 8000,

    data: {
        // The amount of data to initially use.
        size: 2 * 1024 * 1024, // 2 MB

        // If the measure period can't reach the delay defined in the settings,
        // the data amount is multiplied by the following value.
        multiplier: 2
    }
},

download: {
    // Where is located your `network.php` file.
    endpoint: './network.php',
    // The delay while you want to take measures.
    delay: 8000,

    data: {
        // The amount of data to initially use.
        size: 10 * 1024 * 1024, // 10 MB

        // If the measure period can't reach the delay defined in the settings,
        // the data amount is multiplied by the following value.
        multiplier: 1
    }
}

}

I dont know whats going on on this.