I encountered this in frappe LMS, but I am pretty sure that this is a general problem.
When uploading a file through frappe/frappe-ui/src/components/FileUploader/FileUploader.vue that is too big, not real UI feedback for this is shown.
Too big means if it is bigger than Max File Size (MB) in System Settings or client_max_body_size in nginx.conf.
In this case the browser console shows this:
/api/method/upload_file:1 Failed to load resource: the server responded with a status of 413 (REQUEST ENTITY TOO LARGE)
Example from frappe LMS:

The button "Upload an ZIP file" does show a progress with percentages, but afterwards just reverts back to it's initial text.
I encountered this in frappe LMS, but I am pretty sure that this is a general problem.
When uploading a file through
frappe/frappe-ui/src/components/FileUploader/FileUploader.vuethat is too big, not real UI feedback for this is shown.Too big means if it is bigger than
Max File Size (MB)inSystem Settingsorclient_max_body_sizeinnginx.conf.In this case the browser console shows this:
Example from frappe LMS: