Hi there,
in Dashboard > Tools > Site Health –> Info >>> Server tab you can see you server settings.
For comparison these are my base settings for my basic servers:
PHP max input variables 4000
PHP time limit 1200
PHP memory limit 768M
Max input time 600
Upload max filesize 300M
PHP post max size 300M
If you can update you settings to something similar.
But apart from the lower values, what MAY be an issue is the missing unit values for the PHP memory limit, Upload max filesize and PHP post max size.
For example my Upload max filesize is 300M
whereas your server is just 256
So if go to my sites Media > Add New page i will see:
Maximum upload file size: 300M.
Thats 300meg uplaod.
On your site it is:
Maximum upload file size: 256 B.
i could assume thats 256 bytes…. not sure….
If thats the case then the link will expire because the server won’t allow a file over 256 bytes.