File uploads report failed, when successful

Could use some help resolving an upload issue.

I’m using Nextcloud off of a third-party storage company. Works fine so far, except a couple of issues that seems to be part of the Nextcloud functioning rather than the installation of Nextcloud. This concerns Nextcloud v20.0.5.

If I allow for outside people to upload to a folder, by sharing the folder and setting the share type to “File drop (upload only)”, then every file that gets uploaded signals as a failed upload.

The file upload process goes up to 100%, and at 100% the percentage counter text changes to the text “FINISHED”. Things remain like that for 10 seconds or so, and then a small black icon appears to the left of the uploaded file name, and a drop-down announcement appears in the upper right corner of the browser saying “Could not upload [filename]”.

See screenshot.

When I look in the upload folder on the server, the uploaded file is there, fully uploaded and functioning 100%, even though Nextcloud clearly reports an upload fail. The problem seems to be that this “Could not upload” message is shown whether the file upload succeeds or not.

This happens regardless of file size, file type, and upload speed. I have tried uploading in 5 different browsers, with and without script- and ad-blockers, and with firewall on and off. There is no hardware switch/router or firewall in my internet connection and my connection speed is 100mbit.

If I allow for outside people to upload to the same folder, by setting the shared folder to “Allow upload and editing” mode, then the uploads work better. When a file upload actually does fail, in this upload setting, then a drop-down announcement appears in the upper right corner of the browser saying “An unknown error has occurred”. In these cases, there is no uploaded file in the folder afterwards, contrary to the above scenario where there is a file in the folder even though the announcement said “could not upload”.

It is clear that the upload function seems to work in a dodgy manner. Whoever tries to upload, may get a false indication that their upload continuously fails.

I am not sure if there is a setting that needs adjusting to solve this, or what is wrong here? The company I’m hiring Nextcloud from, says that their installation is textbook 101, and I have found no reason to suspect otherwise. I would appreciate advice about where to seek the solution for this, or at least if someone can can replicate the problem.