I implemented the simple uploading file functions that allow users to select files and upload them to the AWS S3 bucket.

when the file dialog popup after clicking the file upload button, I select the file from the network folder (internal network server storage, not local storage) to upload. The uploading is working fine and the file was uploaded correctly, but during the file uploading, other HTTP request calls take more than 40 seconds to receive the response (normally it takes less than 200ms).

This only happens in the firefox. Chrome and other browser work fine. If I upload files from the local storage, everything works just fine. so, this issue occurs only if uploading files from the network server storage in the firefox.

Initially, I thought that the axois that I used may have some issue, so I used fetch to check the issue, and both have the same issue.

Network tab doesn't even show the http request that I sent. It seems like something blocks the request during the file uploading. more than a few tries, some request went through and I checked the network tab items.

and there are three items. first one is http request method: OPTION and the timings tab shows blocked: 6.79s, waiting: 5.93 s.

next one is the same OPTION with blocked: 12.69s, waiting: 5.92 s.

the last one is finally GET blocked: 5.91s, waiting: 7.60 s.

after the file uploading is completed, everything works as normal.

Does anyone have any idea?