kendoUpload multiple files UI freeza and upload fail

[Adam]

We're using kendoUpload control in a .NET MVC project, when selecting multiple files that are tiny in size there is no problem to select and upload many (37 txt files with a size close to 0 used in example). But when trying upload as little as 6 files with a size of around 400Kb the ui seems to upload 1 file, freeze and after some 20 - 30 seconds returns an upload error (hits the "error" method of the kendoUpload object that is).

$("#files").kendoUpload({
    async: {
        chunkSize: 2048000,
        concurrent: false,
        saveUrl: infra.App.baseUrl + "Api/Upload/AdicionarAnexos/" + wbc.Upload.sPastaDestino + "/" + wbc.Upload.nCdModulo,
        autoUpload: false,
    },

...

}

[Martin]

Hello, Adam,

Could you please let me know if the issue can be observed in this Dojo example? I was able to select 6 files at combined size > 1mb and they uploaded successfully.

Regards,
Martin
Progress Telerik

[Adam]

Hi Martin! It wasn't possible to observe the issue in the Dojo example provided, our version in this project was and still is (and will be) Kendo UI v2016.3.914. 

Suprisingly I'm not able to reproduce this error again, it seems like it's working fine now.

I'm back here because we have a similar problem, but of an intermittent nature that has been reproduced in our environment and recorded (only once), and it happens occasionally in one of our clients seemingly without any pattern (only sometimes):

For as little as one document, the progress bar of loading get up to 100% and doesn't go ahead further - is not being received on the server. So far, we haven't been able to find a pattern for this to happen, neither was our client. The below is an image of our upload attachment component, when the processing succeeds, the file names from the top are erased and the file appears on the grid below.

https://drive.google.com/file/d/14qGfYs8qiMDVuz0AY-eK5mkGLEtjXmL7/view?usp=sharing

Any suggestions ??

[Martin]

Hello, Adam,

Unfortunately the provided information and the video do not help me to be 100% sure what is happening. Could you please let me know if a request is being made to the server when the uploading is complete? If a request is made, but no files are sent, please verify that the naming of the parameter that is being sent and the name of the Upload's element are the same. A similar issue seems to be discussed in this forum thread. If that does not resolve the issue, kindly provide a runnable example/project where we can observe the problem and debug it.

[Adam]

Hi Martin!

Thanks for the update.

The major difficulty we are having is the fact that we can't seem to be able to reproduce it anymore. From what I understood, the request is not being made at all, but we don't have enough data to confirm this. I'll get back here again when/if we can find a pattern that allows to reproduce this problem.