Upload file stuck at processing then error


Some members of my team have discovered that the web or desktop app cannot successfully upload files. It took some time on “Processing”, then become “An error occurred while uploading the file” (on Windows PC.)
And I can’t find any specific error message in mattermost.log via searching the user’s id.
Is there any way I can fix this?


Thanks in advance!

Hi YiruChen,

what Mattermost server and client versions are you using?
Are only users with specific teams or permission roles affected or are only specific channels affected?
Can these users upload files to their own 1:1 channel?
Are all files affected or just specific files?

Hi Agriesser,

we use Mattermost server 5.31.6 and client 5.2.0(the one download from here) .
These users cannot upload any file to any channel (include public channel, private channel and to their own 1:1 channel)

Hi Yiruchen, can you look through your mattermost.log file for any errors? I am not sure if the log line would be tied to the user’s id. Please ensure to set the log level at DEBUG.

Can you reproduce this behaviour in the webclient when you directly connect to https:// in your webbrowser and try to upload a file there or when using the mobile clients?
Was this problem introduced recently or has this always been around?

Also, need to say it, 5.31.6 is very old - you should definitely consider to update your insatllation to a newer version sometime soon (make sure to read the important upgrade notes since you’re using a rather old version, you will have to do that in two steps with first upgrading to 5.37.10 f.ex.)

It appears to be a proxy issue, after we properly set the proxy, it works, thanks!

1 Like

can you please explain, what was issue in the proxy server? and how you fixed, we are facing the same issue.

I just remove the exceptions from proxy settings.


I am really sorry, I can’t see this option, where I can find this.

i have main server on 1 VPS and Proxy server on another Vps both use ubuntu .

This is a screenshot of local proxy exceptions from a windows client OS (internet options in control center). Not sure if this relates to your problem but I suggest to open a new topic (since this one is already closed) and provide some more details about your deployment and error messages you’re seeing and we can work on your issue there then.

Thanks for the help. Yes my issue is not related to windows proxy settings.

I have posted my question, if anyone can help.