Check Baloo's BKM https://una.io/page/view-discussion?id=7424

Especially your php.ini setting

On the server side (php.ini) side, these 3 values are important and ideally like this:

max_execution_time = 360

max_input_time = 360

memory_limit = 512M (minimum)

Important: The "upload_max_filesize" and "post_max_size" values of your server (php.ini) will always take precedence over the UNA settings.