Failed to send epub file from mobile browser

[GanniPiece]

Platform: MacOS / Android / Kobo Ereader Browser: Edge

I tried to send the same .epub file from the edge browser on my macbook and on my android mobile to my kobo ereader. The file was successfully sent from my laptop, but failed on the mobile browser.

There is an error message: "Invalid file submitted" when I tried to send the epub file from the mobile browser.