8 – Uploading a large file from the phone doesn’t work

I am using Drupal 8.9.13 and Webform 8.x-5.19. I created a form with only one field, File. (For testing purposes, I put also the file upload field). Drag and drop is also enabled.

I increased the file upload size and the maximum post size to 20 MB.

Uploading files works fine in desktop and laptop, but from a phone/mobile device it doesn’t work. The background process (AJAX) of file uploading goes into a endless loop.

Any solution/suggestion is welcome.

Thanks in advance.